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Many international, national, state, and local organizations prioritize the ranking of threatened and endangered species to help direct conservation efforts. For example, the International Union for Conservation of Nature (IUCN) assesses the Green Status of species and publishes the influential Red List of threatened species. Unfortunately, such conservation yardsticks do not explicitly consider genetic or genomic diversity (GD), even though GD is positively associated with contemporary evolutionary fitness, individual viability, and with future evolutionary potential. To test whether populations of genome sequences could help improve conservation assessments, we estimated GD metrics from 82 publicly available mammalian datasets and examined their statistical association with attributes related to conservation. We also considered intrinsic biological factors, including trophic level and body mass, that could impact GD and quantified their relative influences. Our results identify key population GD metrics that are both reflective and predictive of IUCN conservation categories. Specifically, our analyses revealed that Watterson's theta (the population mutation rate) and autozygosity (a product of inbreeding) are associated with the current Red List categorization, likely because demographic declines that lead to "listing" decisions also reduce levels of standing genetic variation. We argue that by virtue of this relationship, conservation organizations like IUCN could leverage emerging genome sequence data to help categorize Red List threat rankings (especially in otherwise data‐deficient species) and/or enhance Green Status assessments to establish a baseline for future population monitoring. Thus, our paper (1) outlines the theoretical and empirical justification for a new GD‐based assessment criterion, (2) provides a bioinformatic pipeline for estimating GD from population genomic data, and (3) suggests an analytical framework that can be used to measure baseline GD while providing quantitative GD context for consideration by conservation authorities. [ABSTRACT FROM AUTHOR]

Recent developments within the IUCN and the Convention on Biological Diversity have affirmed the increasingly key role that effective population size (Ne) and the effective size: census size ratio (Ne/N) play in applied conservation and management of global biodiversity. This paper reviews and synthesizes information regarding the definition of Ne and demographic and genetic methods for estimating effective size, census size, and their ratio. Emphasis is on single‐generation estimates of contemporary Ne/N, which are the most informative for practical applications. It is crucial to clearly define which individuals are included in the census size (N). Defining N as the number of adults alive at a given time facilitates comparisons across species. For a wide range of applications and experimental designs, inbreeding Ne is simpler to calculate and interpret than variance Ne. Effects of skewed sex ratio are generally modest, so most reductions to Ne/N arise from overdispersed (greater‐than‐Poisson) variance in offspring number (σk2$$ {\sigma}_k^2 $$). Even when fecundity changes with age, overdispersed within‐age variance generally contributes most to overall σk2$$ {\sigma}_k^2 $$, and both random and deterministic (mediated by selection) factors can be important. Most species are age‐structured, so it is important to distinguish between effective size per generation (Ne) and the effective number of breeders in one season or year (Nb). Both Ne and Nb are important for applied conservation and management. For iteroparous species, a key metric is variance in lifetime reproductive success (σk•2$$ {\sigma}_{k\bullet}^2 $$), which can be affected by a variety of additional factors, including variation in longevity, skip or intermittent breeding, and persistent individual differences in reproductive success. Additional factors that can be important for some species are also discussed, including mating systems, population structure, sex reversal, reproductive compensation, captive propagation, and delayed maturity. [ABSTRACT FROM AUTHOR]

The introduction of non‐native species across the world represents a major global challenge. Retracing invasion origin is an important first step in understanding the invasion process, often requiring detailed sampling within the native range. Insect species frequently host Wolbachia, a widespread endosymbiotic bacterium that manipulates host reproduction to increase infected female fitness. Here, we draw on the spatial variation in infection frequencies of an actively spreading Wolbachia strain wCer2 to investigate the invasion origin of the European cherry fruit fly, Rhagoletis cerasi. This pest of cherries was introduced from Europe to North America within the last decade. First, we screen the introduced fly population for the presence of Wolbachia. The introduced populations lack the wCer2 strain and the strongly associated mitochondrial haplotype, suggesting strain absence due to founder effects with invading individuals originating from wCer2‐uninfected native population(s). To narrow down geographic regions of invasion origin, we perform spatial interpolation of the wCer2 infection frequency across the native range and predict the infection frequency in unsampled regions. For this, we use an extensive dataset of R. cerasi infection covering 238 populations across Europe over 25 years, complemented with 14 additional populations analyzed for this study. We find that R. cerasi was unlikely introduced from wCer2‐infected populations in Central and Western Europe. We propose wCer2‐uninfected populations from Eastern Europe and the Mediterranean region as the most likely candidates for the invasion origin. This work utilizes Wolbachia as an indirect instrument to provide insights into the invasion source of R. cerasi in North America, revealing yet another application for this multifaceted heritable endosymbiont. Given the prevalence of biological invasions, rapidly uncovering invasion origins gives fundamental insights into how invasive species adapt to new environments. [ABSTRACT FROM AUTHOR]

Knowledge about sex‐specific difference in life‐history traits—like growth, mortality, or behavior—is of key importance for management and conservation as these parameters are essential for predictive modeling of population sustainability. We applied a newly developed molecular sex identification method, in combination with a SNP (single nucleotide polymorphism) panel for inferring the population of origin, for more than 300 large Atlantic bluefin tuna (ABFT) collected over several years from newly reclaimed feeding grounds in the Northeast Atlantic. The vast majority (95%) of individuals were genetically assigned to the eastern Atlantic population, which migrates between spawning grounds in the Mediterranean and feeding grounds in the Northeast Atlantic. We found a consistent pattern of a male bias among the eastern Atlantic individuals, with a 4‐year mean of 63% males (59%–65%). Males were most prominent within the smallest (< 230 cm) and largest (> 250 cm) length classes, while the sex ratio was close to 1:1 for intermediate sizes (230–250 cm). The results from this new, widely applicable, and noninvasive approach suggests differential occupancy or migration timing of ABFT males and females, which cannot be explained alone by sex‐specific differences in growth. Our findings are corroborated by previous traditional studies of sex ratios in dead ABFT from the Atlantic, the Mediterranean, and the Gulf of Mexico. In concert with observed differences in growth and mortality rates between the sexes, these findings should be recognized in order to sustainably manage the resource, maintain productivity, and conserve diversity within the species. [ABSTRACT FROM AUTHOR]

Populations of marine top predators have been sharply declining during the past decades, and one‐third of chondrichthyans are currently threatened with extinction. Sustainable management measures and conservation plans of large pelagic sharks require knowledge on population genetic differentiation and demographic connectivity. Here, we present the case of the Mediterranean blue shark (Prionace glauca, L. 1758), commonly found as bycatch in longline fisheries and classified by the IUCN as critically endangered. The management of this species suffers from a scarcity of data about population structure and connectivity within the Mediterranean Sea and between this basin and the adjacent Northeast Atlantic. Here, we assessed the genetic diversity and spatial structure of blue shark from different areas of the Mediterranean Sea and the Northeast Atlantic through genome scan analyses. Pairwise genetic differentiation estimates (FST) on 203 specimens genotyped at 14,713 ddRAD‐derived SNPs revealed subtle, yet significant, genetic differences within the Mediterranean sampling locations, and between the Mediterranean Sea and the Northeast Atlantic Ocean. Genetic differentiation suggests some degree of demographic independence between the Western and Eastern Mediterranean blue shark populations. Furthermore, results show limited genetic connectivity between the Mediterranean and the Atlantic basins, supporting the hypothesis of two distinct populations of blue shark separated by the Strait of Gibraltar. Although reproductive interactions may be limited, the faint genetic signal of differentiation suggests a recent common history between these units. Therefore, Mediterranean blue sharks may function akin to a metapopulation relying upon local demographic processes and connectivity dynamics, whereby the limited contemporary gene flow replenishment from the Atlantic may interplay with currently poorly regulated commercial catches and large‐scale ecosystem changes. Altogether, these results emphasise the need for revising management delineations applied to these critically endangered sharks. [ABSTRACT FROM AUTHOR]

Whole‐genome duplication (polyploidy) poses many complications but is an important driver for eukaryotic evolution. To experimentally study how many challenges from the cellular (including gene expression) to the life history levels are overcome in polyploid evolution, a system in which polyploidy can be reliably induced and sustained over generations is crucial. Until now, this has not been possible with animals, as polyploidy notoriously causes first‐generation lethality. The parasitoid wasp Nasonia vitripennis emerges as a stunningly well‐suited model. Polyploidy can be induced in this haplodiploid system through (1) silencing genes in the sex determination cascade and (2) by colchicine injection to induce meiotic segregation failure. Nasonia polyploids produce many generations in a short time, making them a powerful tool for experimental evolution studies. The strong variation observed in Nasonia polyploid phenotypes aids the identification of polyploid mechanisms that are the difference between evolutionary dead ends and successes. Polyploid evolution research benefits from decades of Nasonia research that produced extensive reference—omics data sets, facilitating the advanced studies of polyploid effects on the genome and transcriptome. It is also possible to create both inbred lines (to control for genetic background effects) and outbred lines (to conduct polyploid selection regimes). The option of interspecific crossing further allows to directly contrast autopolyploidy (intraspecific polyploidy) to allopolyploidy (hybrid polyploidy). Nasonia can also be used to investigate the nascent field of using polyploidy in biological control to improve field performance and lower ecological risk. In short, Nasonia polyploids are an exceptional tool for researching various biological paradigms. [ABSTRACT FROM AUTHOR]

Improving the understanding of the causes and effects of anthropogenic hybridization is fundamental to ensure species conservation, particularly in the case of hybridization between wild species and their domestic relatives. Knowledge is missing for many species also because of a lack of appropriate tools for hybrid identification. Here, coupling genotype and phenotype analysis, we carried out an extensive investigation of ongoing hybridization in Alpine ibex Capra ibex, a mountain ungulate of conservation concern from a genetic perspective. By genotyping 63 diagnostic and 465 neutral SNPs, 20 suspected hybrids and 126 Alpine ibex without suspicious phenotype, representing 8 populations across a major part of the species distribution, we found evidence for ongoing hybridization between Alpine ibex and domestic goat. We identified different levels of hybridization including backcrosses into both Alpine ibex and domestic goat. Our results suggest a lack of reproductive barriers between the two species and good survival and reproductive success of the hybrids. Hybridization was locally intense, like a hybrid swarm, but not spread across the rest of the species distribution. Most of the hybrids were discovered in two locations in the north‐west of Italy, while random sampling of individuals from different areas did not provide evidence of recent hybridization. Our method, based on amplicon sequencing of 63 diagnostic SNPs specifically developed for this purpose, allowed us to identify hybrids and backcrosses up to the fourth to fifth generations and was suitable for genetic samples of different quality, although with varying levels of certainty regarding the exact number of generations passed since hybridization. Based on the paired analysis of genotype and phenotype, we provide guidelines for the first identification of hybrids in the field and suggest a procedure for the reliable identification of hybrids. [ABSTRACT FROM AUTHOR]

Conservation and sustainable management of lineages providing non‐timber forest products are imperative under the current global biodiversity loss. Most non‐timber forest species, however, lack genomic studies that characterize their intraspecific variation and evolutionary history, which inform species' conservation practices. Contrary to many lineages in the Andean biodiversity hotspot that exhibit high diversification, the genus Parajubaea (Arecaceae) has only three species despite the genus' origin 22 million years ago. Two of the three palm species, P. torallyi and P. sunkha, are non‐timber forest species endemic to the Andes of Bolivia and are listed as IUCN endangered. The third species, P. cocoides, is a vulnerable species with unknown wild populations. We investigated the evolutionary relationships of Parajubaea species and the genetic diversity and structure of wild Bolivian populations. Sequencing of five low‐copy nuclear genes (3753 bp) challenged the hypothesis that P. cocoides is a cultigen that originated from the wild Bolivian species. We further obtained up to 15,134 de novo single‐nucleotide polymorphism markers by genotyping‐by‐sequencing of 194 wild Parajubaea individuals. Our total DNA sequencing effort rejected the taxonomic separation of the two Bolivian species. As expected for narrow endemic species, we observed low genetic diversity, but no inbreeding signal. We found three genetic clusters shaped by geographic distance, which we use to propose three management units. Different percentages of missing genotypic data did not impact the genetic structure of populations. We use the management units to recommend in situ conservation by creating new protected areas, and ex situ conservation through seed collection. [ABSTRACT FROM AUTHOR]

In combination therapy, bacteria are challenged with two or more antibiotics simultaneously. Ideally, separate mutations are required to adapt to each of them, which is a priori expected to hinder the evolution of full resistance. Yet, the success of this strategy ultimately depends on how well the combination controls the growth of bacteria with and without resistance mutations. To design a combination treatment, we need to choose drugs and their doses and decide how many drugs get mixed. Which combinations are good? To answer this question, we set up a stochastic pharmacodynamic model and determine the probability to successfully eradicate a bacterial population. We consider bacteriostatic and two types of bactericidal drugs—those that kill independent of replication and those that kill during replication. To establish results for a null model, we consider non‐interacting drugs and implement the two most common models for drug independence—Loewe additivity and Bliss independence. Our results show that combination therapy is almost always better in limiting the evolution of resistance than administering just one drug, even though we keep the total drug dose constant for a 'fair' comparison. Yet, exceptions exist for drugs with steep dose–response curves. Combining a bacteriostatic and a bactericidal drug which can kill non‐replicating cells is particularly beneficial. Our results suggest that a 50:50 drug ratio—even if not always optimal—is usually a good and safe choice. Applying three or four drugs is beneficial for treatment of strains with large mutation rates but adding more drugs otherwise only provides a marginal benefit or even a disadvantage. By systematically addressing key elements of treatment design, our study provides a basis for future models which take further factors into account. It also highlights conceptual challenges with translating the traditional concepts of drug independence to the single‐cell level. [ABSTRACT FROM AUTHOR]

Growing evidence indicates that human activities are causing cancer rates to rise in both human and wildlife populations. This is due to the inability of ancestral anti‐cancer defences to cope with modern environmental risks. The evolutionary mismatch between modern oncogenic risks and evolved cancer defences has far‐reaching effects on various biological aspects at different timeframes, demanding a comprehensive study of the biology and evolutionary ecology of the affected species. Firstly, the increased activation of anti‐cancer defences leads to excessive energy expenditure, affecting other biological functions and potentially causing health issues like autoimmune diseases. Secondly, tumorigenesis itself can impact important fitness‐related parameters such as competitiveness, predator evasion, resistance to parasites, and dispersal capacity. Thirdly, rising cancer risks can influence the species' life‐history traits, often favoring early reproduction to offset fitness costs associated with cancer. However, this strategy has its limits, and it may not ensure the sustainability of the species if cancer risks continue to rise. Lastly, some species may evolve additional anti‐cancer defences, with uncertain consequences for their biology and future evolutionary path. In summary, we argue that the effects of increased exposure to cancer‐causing substances on wildlife are complex, ranging from immediate responses to long‐term evolutionary changes. Understanding these processes, especially in the context of conservation biology, is urgently needed. [ABSTRACT FROM AUTHOR]

The interest in recirculating aquaculture systems (RAS) is growing due to their benefits such as increased productivity, better control over animal care, reduced environmental effects, and less water consumption. However, in some regions of the world, traditional aquaculture methods remain prevalent, and selective breeding has often been designed for performance within these systems. Therefore, it is important to evaluate how current fish populations fare in RAS to guide future breeding choices. In a commercial setting, we explore the genetic structure of growth characteristics, measure genotype–environment interactions (GxE) in salmon smolts, and examine genetic markers related to growth in freshwater lochs and RAS. Young salmon were raised together until they reached the parr stage, after which they were divided equally between freshwater net‐pens and RAS. After an 8‐week period, we sampled fish from each environment and genotyped them. Our findings revealed that fish reared in RAS were generally smaller in weight and length but exhibited a higher condition factor and uniformity. We found a notably smaller component of unexplained variance in the RAS, leading to higher heritability estimates. We observed a low GxE effect for length and condition factor, but significant re‐ranking for whole‐body weight, as well as noticeable differences in trait associations across environments. Specifically, a segment of chromosome 22 was found to be linked with the condition factor in the RAS population only. Results suggests that if the use of RAS continues to expand, the efficiency of existing commercial populations may not reach its full potential unless breeding programs specific to RAS are implemented. [ABSTRACT FROM AUTHOR]

Species distribution models (SDMs) are often built upon the "niche conservatism" assumption, such that they ignore the possibility of "evolutionary rescue" and may underestimate species' future range limits under climate change. We select aphids and ladybirds as model species and develop an eco‐evolutionary model to explore evolutionary rescue in a predator–prey system under climate change. We model the adaptive change of species' thermal performances, accounting for biotic interactions. Our study suggests that, without considering evolutionary adaptation, the warming climate will result in a reduction in aphid populations and the extinction of ladybirds in large parts of the United States. However, when incorporating evolutionary adaptation into the model, aphids can adapt to climate change, whereas ladybirds demonstrate geographic variation in their evolutionary rescue potential. Specifically, ladybirds in southern regions are more likely to be rescued than those in the north. In certain northern regions, ladybirds do not avoid extinction due to severe warming trends and seasonality of the climate. While higher warming trends do prompt stronger evolutionary changes in phenotype, they also lead to reduced aphid population abundance such that ecology constrains ladybird population growth. Higher seasonality induces an ecological effect by limiting the length of reproductive season, thereby reducing the capacity for evolutionary rescue. Together, these findings reveal the complex interplay between ecological and evolutionary dynamics in the context of evolutionary adaptation to climate change. [ABSTRACT FROM AUTHOR]

Phenotypic plasticity can buffer organisms against short‐term environmental fluctuations. For example, previous exposure to increased temperatures can increase thermal tolerance in many species. Prior studies have found that acclimation to higher temperature can influence the magnitude of transcriptional response to subsequent acute thermal stress (hereafter, "transcriptional response modulation"). However, mechanisms mediating this gene expression response and, ultimately, phenotypic plasticity remain largely unknown. Epigenetic modifications are good candidates for modulating transcriptional response, as they broadly correlate with gene expression. Here, we investigate changes in DNA methylation as a possible mechanism controlling shifts in gene expression plasticity and thermal acclimation in the reef‐building coral Acropora nana. We find that gene expression response to acute stress is altered in corals acclimated to different temperatures, with many genes exhibiting a dampened response to heat stress in corals pre‐conditioned to higher temperatures. At the same time, we observe shifts in methylation during both acclimation (11 days) and acute heat stress (24 h). We observed that the acute heat stress results in shifts in gene‐level methylation and elicits an acute transcriptional response in distinct gene sets. Further, acclimation‐induced shifts in gene expression plasticity and differential methylation also largely occur in separate sets of genes. Counter to our initial hypothesis no overall correlation between the magnitude of differential methylation and the change in gene expression plasticity. We do find a small but statistically significant overlap in genes exhibiting both dampened expression response and shifts in methylation (14 genes), which could be candidates for further inquiry. Overall, our results suggest transcriptional response modulation occurs independently from methylation changes induced by thermal acclimation. [ABSTRACT FROM AUTHOR]

Biological control of weeds involves deliberate introduction of host‐specific natural enemies into invaded range to reduce the negative impacts of invasive species. Assessing the specificity is a crucial step, as introduction of generalist natural enemies into a new territory may pose risks to the recipient communities. A mechanistic understanding of host use can provide valuable insights for the selection of specialist natural enemies, bolster confidence in non‐target risk assessment and potentially accelerate the host specificity testing process in biological control. We conducted a comprehensive analysis of studies on the genomics of host specialization with a view to examine if genomic signatures can help predict host specificity in insects. Focusing on phytophagous Lepidoptera, Coleoptera and Diptera, we compared chemosensory receptors and enzymes between "specialist" (insects with narrow host range) and "generalist" (insects with wide host range) insects. The availability of genomic data for biological control agents (natural enemies of weeds) is limited thus our analyses utilized data from pest insects and model organisms for which genomic data are available. Our findings revealed that specialists generally exhibit a lower number of chemosensory receptors and enzymes compared with their generalist counterparts. This pattern was more prominent in Coleoptera and Diptera relative to Lepidoptera. This information can be used to reject agents with large gene repertoires to potentially accelerate the risk assessment process. Similarly, confirming smaller gene repertoires in specialists could further strengthen the risk evaluation. Despite the distinctive signatures between specialists and generalists, challenges such as finite genomic data for biological control agents, ad hoc comparisons, and fewer comparative studies among congeners limit our ability to use genomic signatures to predict host specificity. A few studies have empirically compared phylogenetically closely related species, enhancing the resolution and the predictive power of genomics signatures thus suggesting the need for more targeted studies comparing congeneric specialists and generalists. [ABSTRACT FROM AUTHOR]

The deliberate release of captive‐bred individuals, the accidental escape of domesticated strains, or the invasion of closely related conspecifics into wild populations can all lead to introgressive hybridization, which poses a challenge for conservation and wildlife management. Rates of introgression and the magnitude of associated demographic impacts vary widely across ecological contexts. However, the reasons for this variation remain poorly understood. One rarely considered phenomenon in this context is soft selection, wherein relative trait values determine success in intraspecific competition for a limiting resource. Here we develop an eco‐genetic model explicitly focussed on understanding the influence of such competitive interactions on the eco‐evolutionary dynamics of wild populations experiencing an influx of foreign/domesticated individuals. The model is applicable to any taxon that experiences natural or human‐mediated inputs of locally maladapted genotypes ('intrusion'), in addition to phenotype‐dependent competition for a limiting resource (e.g. breeding sites, feeding territories). The effects of both acute and chronic intrusion depended strongly on the relative competitiveness of intruders versus locals. When intruders were competitively inferior, density‐dependent regulation limited their reproductive success (ability to compete for limited spawning sites), which prevented strong introgression or population declines from occurring. In contrast, when intruders were competitively superior, this amplified introgression and led to increased maladaptation of the admixed population. This had negative consequences for population size and population viability. The results were sensitive to the intrusion level, the magnitude of reproductive excess, trait heritability and the extent to which intruders were maladapted relative to locals. Our findings draw attention to under‐appreciated interactions between phenotype‐dependent competitive interactions and maladaptive hybridization, which may be critical to determining the impact captive breeding programmes and domesticated escapees can have on otherwise self‐sustaining wild populations. [ABSTRACT FROM AUTHOR]

Detecting recent demographic changes is a crucial component of species conservation and management, as many natural populations face declines due to anthropogenic habitat alteration and climate change. Genetic methods allow researchers to detect changes in effective population size (Ne) from sampling at a single timepoint. However, in species with long lifespans, there is a lag between the start of a decline in a population and the resulting decrease in genetic diversity. This lag slows the rate at which diversity is lost, and therefore makes it difficult to detect recent declines using genetic data. However, the genomes of old individuals can provide a window into the past, and can be compared to those of younger individuals, a contrast that may help reveal recent demographic declines. To test whether comparing the genomes of young and old individuals can help infer recent demographic bottlenecks, we use forward‐time, individual‐based simulations with varying mean individual lifespans and extents of generational overlap. We find that age information can be used to aid in the detection of demographic declines when the decline has been severe. When average lifespan is long, comparing young and old individuals from a single timepoint has greater power to detect a recent (within the last 50 years) bottleneck event than comparing individuals sampled at different points in time. Our results demonstrate how longevity and generational overlap can be both a hindrance and a boon to detecting recent demographic declines from population genomic data. [ABSTRACT FROM AUTHOR]

The Seychelles magpie‐robin's (SMR) five island populations exhibit some of the lowest recorded levels of genetic diversity among endangered birds, and high levels of inbreeding. These populations collapsed during the 20th century, and the species was listed as Critically Endangered in the IUCN Red List in 1994. An assisted translocation‐for‐recovery program initiated in the 1990s increased the number of mature individuals, resulting in its downlisting to Endangered in 2005. Here, we explore the temporal genomic erosion of the SMR based on a dataset of 201 re‐sequenced whole genomes that span the past ~150 years. Our sample set includes individuals that predate the bottleneck by up to 100 years, as well as individuals from contemporary populations established during the species recovery program. Despite the SMR's recent demographic recovery, our data reveal a marked increase in both the genetic load and realized load in the extant populations when compared to the historical samples. Conservation management may have reduced the intensity of selection by increasing juvenile survival and relaxing intraspecific competition between individuals, resulting in the accumulation of loss‐of‐function mutations (i.e. severely deleterious variants) in the rapidly recovering population. In addition, we found a 3‐fold decrease in genetic diversity between temporal samples. While the low genetic diversity in modern populations may limit the species' adaptability to future environmental changes, future conservation efforts (including IUCN assessments) may also need to assess the threats posed by their high genetic load. Our computer simulations highlight the value of translocations for genetic rescue and show how this could halt genomic erosion in threatened species such as the SMR. [ABSTRACT FROM AUTHOR]

Chinook salmon (Oncorhynchus tshawytscha) display remarkable life history diversity, underpinning their ability to adapt to environmental change. Maintaining life history diversity is vital to the resilience and stability of Chinook salmon metapopulations, particularly under changing climates. However, the conditions that promote life history diversity are rapidly disappearing, as anthropogenic forces promote homogenization of habitats and genetic lineages. In this study, we use the highly modified Yuba River in California to understand if distinct genetic lineages and life histories still exist, despite reductions in spawning habitat and hatchery practices that have promoted introgression. There is currently a concerted effort to protect federally listed Central Valley spring‐run Chinook salmon populations, given that few wild populations still exist. Despite this, we lack a comprehensive understanding of the genetic and life history diversity of Chinook salmon present in the Yuba River. To understand this diversity, we collected migration timing data and GREB1L genotypes from hook‐and‐line, acoustic tagging, and carcass surveys of Chinook salmon in the Yuba River between 2009 and 2011. Variation in the GREB1L region of the genome is tightly linked with run timing in Chinook salmon throughout their range, but the relationship between this variation and entry on spawning grounds is little explored in California's Central Valley. We found that the date Chinook salmon crossed the lowest barrier to Yuba River spawning habitat (Daguerre Point Dam) was tightly correlated with their GREB1L genotype. Importantly, our study confirms that ESA‐listed spring‐run Chinook salmon are spawning in the Yuba River, promoting a portfolio of life history and genetic diversity, despite the highly compressed habitat. This work highlights the need to identify and protect this life history diversity, especially in heavily impacted systems, to maintain healthy Chinook salmon metapopulations. Without protection, we run the risk of losing the last vestiges of important genetic variation. [ABSTRACT FROM AUTHOR]

For almost 200 years, the taxonomy of cutthroat trout (Oncorhynchus clarkii), a salmonid native to Western North America, has been in flux as ichthyologists and fisheries biologists have tried to describe the diversity within these fishes. Starting in the 1950s, Robert Behnke reexamined the cutthroat trout and identified 14 subspecies based on morphological traits, Pleistocene events, and modern geographic ranges. His designations became instrumental in recognizing and preserving the remaining diversity of cutthroat trout. Over time, molecular techniques (i.e. karyotypes, allozymes, mitochondrial DNA, SNPs, and microsatellite arrays) have largely reinforced Behnke's phylogenies, but have also revealed that some relationships are consistently weakly supported. To further resolve these relationships, we generated de novo transcriptomes for nine cutthroat subspecies, as well as a Bear River Bonneville form and two Colorado River lineages (blue and green). We present phylogenies of these subspecies generated from multiple sets of orthologous genes extracted from our transcriptomes. We confirm many of the relationships identified in previous morphological and molecular studies, as well as discuss the importance of significant differences apparent in our phylogenies from these studies within a geological perspective. Specific findings include three distinct clades: (1) Bear River Bonneville form and Yellowstone cutthroat trout; (2) Bonneville cutthroat trout (n = 2); and (3) Greenback and Rio Grande cutthroat trout. We also identify potential gene transfer between Bonneville cutthroat trout and a population of Colorado River green lineage cutthroat trout. Using these findings, it appears that additional groups warrant species‐level consideration if other recent species elevations are retained. [ABSTRACT FROM AUTHOR]

This article summarizes the Special Issue of Evolutionary Applications focused on "Advances in Salmonid Genetics." Contributions to this Special Issue were primarily presented at the Coastwide Salmonid Genetics Meeting, held in Boise, ID in June 2023, with a focus on Pacific salmonids of the west coast region of North America. Contributions from other regions of the globe are also included and further convey the importance of various salmonid species across the world. This Special Issue is comprised of 22 articles that together illustrate major advances in genetic and genomic tools to address fundamental and applied questions for natural populations of salmonids, ranging from mixed‐stock analyses, to conservation of genetic diversity, to adaptation to local environments. These studies provide valuable insight for molecular ecologists since salmonid systems offer a window into evolutionary applications that parallel conservation efforts relevant and applicable beyond salmonid species. Here, we provide an introduction and a synopsis of articles in this Special Issue, along with future directions in this field. We present this Special Issue in honor of Fred Utter, a founder and leader in the field of salmonid genetics, who passed away in 2023. [ABSTRACT FROM AUTHOR]

There are two primary measures of the amount of genetic variation in a population at a locus: heterozygosity and the number of alleles. Effective population size (Ne) provides both an expectation of the amount of heterozygosity in a population at drift‐mutation equilibrium and the rate of loss of heterozygosity because of genetic drift. In contrast, the number of alleles in a population at drift‐mutation equilibrium is a function of both Ne and census size (NC). In addition, populations with the same Ne can lose allelic variation at very different rates. Allelic variation is generally much more sensitive to bottlenecks than heterozygosity. Expressions used to adjust for the effects of violations of the ideal population on Ne do not provide good predictions of the loss of allelic variation. These effects are much greater for loci with many alleles, which are often important for adaptation. We show that there is a linear relationship between the reduction of NC and the corresponding reduction of the expected number of alleles at drift‐mutation equilibrium. This makes it possible to predict the expected effect of a bottleneck on allelic variation. Heterozygosity provides good estimates of the rate of adaptive change in the short‐term, but allelic variation provides important information about long‐term adaptive change. The guideline of long‐term Ne being greater than 500 is often used as a primary genetic metric for evaluating conservation status. We recommend that this guideline be expanded to take into account allelic variation as well as heterozygosity. [ABSTRACT FROM AUTHOR]

Given the multitude of challenges Earth is facing, sustainability science is of key importance to our continued existence. Evolution is the fundamental biological process underlying the origin of all biodiversity. This phylogenetic diversity fosters the resilience of ecosystems to environmental change, and provides numerous resources to society, and options for the future. Genetic diversity within species is also key to the ability of populations to evolve and adapt to environmental change. Yet, the value of evolutionary processes and the consequences of their impairment have not generally been considered in sustainability research. We argue that biological evolution is important for sustainability and that the concepts, theory, data, and methodological approaches used in evolutionary biology can, in crucial ways, contribute to achieving the UN Sustainable Development Goals (SDGs). We discuss how evolutionary principles are relevant to understanding, maintaining, and improving Nature Contributions to People (NCP) and how they contribute to the SDGs. We highlight specific applications of evolution, evolutionary theory, and evolutionary biology's diverse toolbox, grouped into four major routes through which evolution and evolutionary insights can impact sustainability. We argue that information on both within‐species evolutionary potential and among‐species phylogenetic diversity is necessary to predict population, community, and ecosystem responses to global change and to make informed decisions on sustainable production, health, and well‐being. We provide examples of how evolutionary insights and the tools developed by evolutionary biology can not only inspire and enhance progress on the trajectory to sustainability, but also highlight some obstacles that hitherto seem to have impeded an efficient uptake of evolutionary insights in sustainability research and actions to sustain SDGs. We call for enhanced collaboration between sustainability science and evolutionary biology to understand how integrating these disciplines can help achieve the sustainable future envisioned by the UN SDGs. [ABSTRACT FROM AUTHOR]

Climate change poses a particular threat to long‐lived trees, which may not adapt or migrate fast enough to keep up with rising temperatures. Assisted gene flow could facilitate adaptation of populations to future climates by using managed translocation of seeds from a warmer location (provenance) within the current range of a species. Finding the provenance that will perform best in terms of survival or growth is complicated by a trade‐off. Because trees face a rapidly changing climate during their long lives, the alleles that confer optimal performance may vary across their lifespan. For instance, trees from warmer provenances could be well adapted as adults but suffer from colder temperatures while juvenile. Here we use a stage‐structured model, using both analytical predictions and numerical simulations, to determine which provenance would maximize the survival of a cohort of long‐lived trees in a changing climate. We parameterize our simulations using empirically estimated demographic transition matrices for 20 long‐lived tree species. Unable to find reliable quantitative estimates of how climatic tolerance changes across stages in these same species, we varied this parameter to study its effect. Both our mathematical model and simulations predict that the best provenance depends strongly on how fast the climate changes and also how climatic tolerance varies across the lifespan of a tree. We thus call for increased empirical efforts to measure how climate tolerance changes over life in long‐lived species, as our model suggests that it should strongly influence the best provenance for assisted gene flow. [ABSTRACT FROM AUTHOR]

Spreading of bacterial and fungal strains that are resistant to antimicrobials poses a serious threat to the well‐being of humans, animals, and plants. Antimicrobial resistance has been mainly investigated in clinical settings. However, throughout their evolutionary history microorganisms in the wild have encountered antimicrobial substances, forcing them to evolve strategies to combat antimicrobial action. It is well known that many of these strategies are based on genetic mechanisms, but these do not fully explain important aspects of the antimicrobial response such as the rapid development of resistance, reversible phenotypes, and hetero‐resistance. Consequently, attention has turned toward epigenetic pathways that may offer additional insights into antimicrobial mechanisms. The aim of this review is to explore the epigenetic mechanisms that confer antimicrobial resistance, focusing on those that might be relevant for resistance in the wild. First, we examine the presence of antimicrobials in natural settings. Then we describe the documented epigenetic mechanisms in bacteria and fungi associated with antimicrobial resistance and discuss innovative epigenetic editing techniques to establish causality in this context. Finally, we discuss the relevance of these epigenetic mechanisms on the evolutionary dynamics of antimicrobial resistance in the wild, emphasizing the critical role of priming in the adaptation process. We underscore the necessity of incorporating non‐genetic mechanisms into our understanding of antimicrobial resistance evolution. These mechanisms offer invaluable insights into the dynamics of antimicrobial adaptation within natural ecosystems. [ABSTRACT FROM AUTHOR]

Urbanization leads to complex environmental changes and poses multiple challenges to organisms. Amphibians are highly susceptible to the effects of urbanization, with land use conversion, habitat destruction, and degradation ranked as the most significant threats. Consequently, amphibians are declining in urban areas, in both population numbers and abundance, however, the effect of urbanization on population genetic parameters remains unclear. Here, we studied the genomic response to urbanization in two widespread European species, the common toad Bufo bufo (26 localities, 480 individuals), and the smooth newt Lissotriton vulgaris (30 localities, 516 individuals) in three geographic regions: southern and northern Poland and southern Norway. We assessed genome‐wide SNP variation using RADseq (ca. 42 and 552 thousand SNPs in toads and newts, respectively) and adaptively relevant major histocompatibility complex (MHC) class I and II genes. The results linked most of the genetic differentiation in both marker types to regional (latitudinal) effects, which also correspond to historical biogeography. Further, we did not find any association between genetic differentiation and level of urbanization at local scales for either species. However, urban smooth newts, but not toads, have lower levels of within‐population genome‐wide diversity, suggesting higher susceptibility to the negative effects of urbanization. A decreasing level of genetic diversity linked to increasing urbanization was also found for MHC II in smooth newts, while the relationship between MHC class I diversity and urbanization differed between geographic regions. We did not find any effects of urbanization on MHC diversity in the toad populations. Although two genetic environment association analyses of genome‐wide data, LFMM and BayPass, revealed numerous (219 in B. bufo and 7040 in L. vulgaris) SNPs statistically associated with urbanization, we found a marked lack of repeatability between geographic regions, suggesting a complex and multifaceted response to natural selection elicited by life in the city. [ABSTRACT FROM AUTHOR]

Intraspecific diversity plays a critical role in the resilience of Chinook salmon populations. California's Central Valley (CV) historically hosted one of the most diverse population complexes of Chinook salmon in the world. However, anthropogenic factors have dramatically decreased this diversity, with severe consequences for population resilience. Here we use next generation sequencing and an archive of thousands of tissue samples collected across two decades during the juvenile outmigration to evaluate phenotypic diversity between and within populations of CV Chinook salmon. To account for highly heterogeneous sample qualities in the archive dataset, we develop and test an approach for population and subpopulation assignments of CV Chinook salmon that allows inclusion of relatively low‐quality samples while controlling error rates. We find significantly distinct outmigration timing and body size distributions for each population and subpopulation. Within the archive dataset, spring run individuals that assigned to the Mill and Deer Creeks subpopulation exhibited an earlier and broader outmigration distribution as well as larger body sizes than individuals that assigned to the Butte Creek subpopulation. Within the fall run population, individuals that assigned to the late‐fall run subpopulation also exhibited an earlier and broader outmigration distribution and larger body sizes than other fall run fish in our dataset. These results highlight the importance of distinct subpopulations for maintaining remaining diversity in CV Chinook salmon, and demonstrates the power of genomics‐based population assignments to aid the study and management of intraspecific diversity. [ABSTRACT FROM AUTHOR]

Ongoing climatic shifts and increasing anthropogenic pressures demand an efficient delineation of conservation units and accurate predictions of populations' resilience and adaptive potential. Molecular tools involving DNA sequencing are nowadays routinely used for these purposes. Yet, most of the existing tools focusing on sequence‐level information have shortcomings in detecting signals of short‐term ecological relevance. Epigenetic modifications carry valuable information to better link individuals, populations, and species to their environment. Here, we discuss a series of epigenetic monitoring tools that can be directly applied to various conservation contexts, complementing already existing molecular monitoring frameworks. Focusing on DNA sequence‐based methods (e.g. DNA methylation, for which the applications are readily available), we demonstrate how (a) the identification of epi‐biomarkers associated with age or infection can facilitate the determination of an individual's health status in wild populations; (b) whole epigenome analyses can identify signatures of selection linked to environmental conditions and facilitate estimating the adaptive potential of populations; and (c) epi‐eDNA (epigenetic environmental DNA), an epigenetic‐based conservation tool, presents a non‐invasive sampling method to monitor biological information beyond the mere presence of individuals. Overall, our framework refines conservation strategies, ensuring a comprehensive understanding of species' adaptive potential and persistence on ecologically relevant timescales. [ABSTRACT FROM AUTHOR]

Spatial agent‐based models are frequently used to investigate the evolution of solid tumours subject to localized cell–cell interactions and microenvironmental heterogeneity. As spatial genomic, transcriptomic and proteomic technologies gain traction, spatial computational models are predicted to become ever more necessary for making sense of complex clinical and experimental data sets, for predicting clinical outcomes, and for optimizing treatment strategies. Here we present a non‐technical step by step guide to developing such a model from first principles. Stressing the importance of tailoring the model structure to that of the biological system, we describe methods of increasing complexity, from the basic Eden growth model up to off‐lattice simulations with diffusible factors. We examine choices that unavoidably arise in model design, such as implementation, parameterization, visualization and reproducibility. Each topic is illustrated with examples drawn from recent research studies and state of the art modelling platforms. We emphasize the benefits of simpler models that aim to match the complexity of the phenomena of interest, rather than that of the entire biological system. Our guide is aimed at both aspiring modellers and other biologists and oncologists who wish to understand the assumptions and limitations of the models on which major cancer studies now so often depend. [ABSTRACT FROM AUTHOR]

Knowledge of functional dispersal barriers in the marine environment can be used to inform a wide variety of management actions, such as marine spatial planning, restoration efforts, fisheries regulations, and invasive species management. Locations and causes of dispersal barriers can be studied through various methods, including movement tracking, biophysical modeling, demographic models, and genetics. Combining methods illustrating potential dispersal, such as biophysical modeling, with realized dispersal through, e.g., genetic connectivity estimates, provides particularly useful information for teasing apart potential causes of observed barriers. In this study, we focus on blue mussels (Mytilus edulis) in the Skagerrak—a marginal sea connected to the North Sea in Northern Europe—and combine biophysical models of larval dispersal with genomic data to infer locations and causes of dispersal barriers in the area. Results from both methods agree; patterns of ocean currents are a major structuring factor in the area. We find a complex pattern of source‐sink dynamics with several dispersal barriers and show that some areas can be isolated despite an overall high dispersal capability. Finally, we translate our finding into management advice that can be used to sustainably manage this ecologically and economically important species in the future. [ABSTRACT FROM AUTHOR]

Genetic assessment of species that have experienced dramatic population declines provides critical information that is instrumental for the design of conservation recovery programs. Here, we use different sources of molecular data (mtDNA and ddRAD‐seq) to evaluate the genetic status of wild and captive populations of marbled teal (Marmaronetta angustirostris), a duck species classified as critically endangered in Spain and near threatened at a global scale. First, we determined the evolutionary and demographic trajectories of the wild population from Spain and the currently much larger population from Iraq, which is also the documented source of European zoo stocks. Second, we evaluated the suitability of the different captive populations for ongoing restocking programs in Spain and assessed their potential impact on the genetic composition of wild populations. Populations from Spain and Iraq were assigned to distinct genetic clusters, albeit with an overall low level of genetic differentiation, in line with their recent divergence (<8000 years ago) and lack of phylogeographic structure in the species. Demogenomic inferences revealed that the two populations have experienced parallel demographic trajectories, with a marked bottleneck during the last glacial period followed by a sudden demographic expansion and stability since the onset of the Holocene. The wild population from Spain presented high levels of inbreeding, but we found no evidence of recent genetic bottlenecks compatible with the human‐driven decline of the species during the past century. The captive populations from the two Spanish centers involved in restocking programs showed genetic introgression from European zoos; however, we found limited evidence of introgression from the zoo genetic stock into the wild population from Spain, suggesting captive‐bred birds have limited breeding success in the wild. Our study illustrates how ex situ conservation programs should consider the genetic distinctiveness of populations when establishing breeding stocks and highlights the importance of genetically assessing captive populations prior to reinforcement actions. [ABSTRACT FROM AUTHOR]

ABSTRACT Many international, national, state, and local organizations prioritize the ranking of threatened and endangered species to help direct conservation efforts. For example, the International Union for Conservation of Nature (IUCN) assesses the Green Status of species and publishes the influential Red List of threatened species. Unfortunately, such conservation yardsticks do not explicitly consider genetic or genomic diversity (GD), even though GD is positively associated with contemporary evolutionary fitness, individual viability, and with future evolutionary potential. To test whether populations of genome sequences could help improve conservation assessments, we estimated GD metrics from 82 publicly available mammalian datasets and examined their statistical association with attributes related to conservation. We also considered intrinsic biological factors, including trophic level and body mass, that could impact GD and quantified their relative influences. Our results identify key population GD metrics that are both reflective and predictive of IUCN conservation categories. Specifically, our analyses revealed that Watterson's theta (the population mutation rate) and autozygosity (a product of inbreeding) are associated with the current Red List categorization, likely because demographic declines that lead to “listing” decisions also reduce levels of standing genetic variation. We argue that by virtue of this relationship, conservation organizations like IUCN could leverage emerging genome sequence data to help categorize Red List threat rankings (especially in otherwise data‐deficient species) and/or enhance Green Status assessments to establish a baseline for future population monitoring. Thus, our paper (1) outlines the theoretical and empirical justification for a new GD‐based assessment criterion, (2) provides a bioinformatic pipeline for estimating GD from population genomic data, and (3) suggests an analytical framework that can be used to measure baseline GD while providing quantitative GD context for consideration by conservation authorities.

Harvesting and culling are methods used to monitor and manage wildlife diseases. An important consequence of these practices is a change in the genetic dynamics of affected populations that may threaten their long‐term viability. The effective population size (Ne) is a fundamental parameter for describing such changes as it determines the amount of genetic drift in a population. Here, we estimate Ne of a harvested wild reindeer population in Norway. Then we use simulations to investigate the genetic consequences of management efforts for handling a recent spread of chronic wasting disease, including increased adult male harvest and population decimation. The Ne/N ratio in this population was found to be 0.124 at the end of the study period, compared to 0.239 in the preceding 14 years period. The difference was caused by increased harvest rates with a high proportion of adult males (older than 2.5 years) being shot (15.2% in 2005–2018 and 44.8% in 2021). Increased harvest rates decreased Ne in the simulations, but less sex biased harvest strategies had a lower negative impact. For harvest strategies that yield stable population dynamics, shifting the harvest from calves to adult males and females increased Ne. Population decimation always resulted in decreased genetic variation in the population, with higher loss of heterozygosity and rare alleles with more severe decimation or longer periods of low population size. A very high proportion of males in the harvest had the most severe consequences for the loss of genetic variation. This study clearly shows how the effects of harvest strategies and changes in population size interact to determine the genetic drift of a managed population. The long‐term genetic viability of wildlife populations subject to a disease will also depend on population impacts of the disease and how these interact with management actions. [ABSTRACT FROM AUTHOR]

As biodiversity loss outpaces recovery, conservationists are increasingly turning to novel tools for preventing extinction, including cloning and in vitro gametogenesis of biobanked cells. However, restoration of populations can be hindered by low genetic diversity and deleterious genetic load. The persistence of the northern white rhino (Ceratotherium simum cottoni) now depends on the cryopreserved cells of 12 individuals. These banked genomes have higher genetic diversity than southern white rhinos (C. s. simum), a sister subspecies that successfully recovered from a severe bottleneck, but the potential impact of genetic load is unknown. We estimated how demographic history has shaped genome‐wide genetic load in nine northern and 13 southern white rhinos. The bottleneck left southern white rhinos with more fixed and homozygous deleterious alleles and longer runs of homozygosity, whereas northern white rhinos retained more deleterious alleles masked in heterozygosity. To gauge the impact of genetic load on the fitness of a northern white rhino population restored from biobanked cells, we simulated recovery using fitness of southern white rhinos as a benchmark for a viable population. Unlike traditional restoration, cell‐derived founders can be reintroduced in subsequent generations to boost lost genetic diversity and relieve inbreeding. In simulations with repeated reintroduction of founders into a restored population, the fitness cost of genetic load remained lower than that borne by southern white rhinos. Without reintroductions, rapid growth of the restored population (>20–30% per generation) would be needed to maintain comparable fitness. Our results suggest that inbreeding depression from genetic load is not necessarily a barrier to recovery of the northern white rhino and demonstrate how restoration from biobanked cells relieves some constraints of conventional restoration from a limited founder pool. Established conservation methods that protect healthy populations will remain paramount, but emerging technologies hold promise to bolster these tools to combat the extinction crisis. [ABSTRACT FROM AUTHOR]

DNA methylation is critical to the regulation of transposable elements and gene expression and can play an important role in the adaptation of stress response mechanisms in plants. Traditional methods of methylation quantification rely on bisulfite conversion that can compromise accuracy. Recent advances in long‐read sequencing technologies allow for methylation detection in real time. The associated algorithms that interpret these modifications have evolved from strictly statistical approaches to Hidden Markov Models and, recently, deep learning approaches. Much of the existing software focuses on methylation in the CG context, but methylation in other contexts is important to quantify, as it is extensively leveraged in plants. Here, we present methylation profiles for two maple species across the full range of 5mC sequence contexts using Oxford Nanopore Technologies (ONT) long‐reads. Hybrid and reference‐guided assemblies were generated for two new Acer accessions: Acer negundo (box elder; 65x ONT and 111X Illumina) and Acer saccharum (sugar maple; 93x ONT and 148X Illumina). The ONT reads generated for these assemblies were re‐basecalled, and methylation detection was conducted in a custom pipeline with the published Acer references (PacBio assemblies) and hybrid assemblies reported herein to generate four epigenomes. Examination of the transposable element landscape revealed the dominance of LTR Copia elements and patterns of methylation associated with different classes of TEs. Methylation distributions were examined at high resolution across gene and repeat density and described within the broader angiosperm context, and more narrowly in the context of gene family dynamics and candidate nutrient stress genes. [ABSTRACT FROM AUTHOR]

Fragmentation of watercourses poses a significant threat to biodiversity, particularly for migratory fish species. Mitigation measures such as fishways, have been increasingly implemented to restore river connectivity and support fish migration. The effects of such restoration efforts are typically tested using telemetry and fisheries methods, which do not fully capture the broader population movements that may have important consequences for population viability. We performed a before‐and‐after control‐impact (BACI) study using genetic tools (SNPs) to investigate the effect of a newly implemented fishway, aiming to enhance upstream spawning migration of brown trout (Salmo trutta Linnaeus) in a reservoir with two headwater tributaries fragmented by man‐made weirs. Another reservoir with two barrier‐free tributaries was also analysed as a control. Our results showed that the isolated brown trout population was spawning in the reservoir before the installation of the fishway, and we found genetic structuring and differentiation between fragmented headwater tributaries before the fishway construction, but not in the control reservoir. Unexpectedly, after the fishway construction we observed signals consistent with increased genetic differentiation between populations of newly recruited juvenile fish in the reservoir tributary and fish in the reservoir. We propose this was caused by newly enabled philopatric behaviour of brown trout to their natal spawning tributary. In contrast, we did not find any genetic changes in the tributary without a fishway or in the barrier‐free reservoir system. Given the scarcity of similar studies, we advocate for an increased use of genetic analyses in BACI studies to monitor and evaluate the effect of efforts to restore habitat connectivity and inform future management strategies. [ABSTRACT FROM AUTHOR]

The decline of lions (Panthera leo) in Kenya has raised conservation concerns about their overall population health and long‐term survival. This study aimed to assess the genetic structure, differentiation and diversity of lion populations in the country, while considering the influence of past management practices. Using a lion‐specific Single Nucleotide Polymorphism (SNP) panel, we genotyped 171 individuals from 12 populations representative of areas with permanent lion presence. Our results revealed a distinct genetic pattern with pronounced population structure, confirmed a north‐south split and found no indication of inbreeding in any of the tested populations. Differentiation seems to be primarily driven by geographical barriers, human presence and climatic factors, but management practices may have also affected the observed patterns. Notably, the Tsavo population displayed evidence of admixture, perhaps attributable to its geographic location as a suture zone, vast size or past translocations, while the fenced populations of Lake Nakuru National Park and Solio Ranch exhibited reduced genetic diversity due to restricted natural dispersal. The Amboseli population had a high number of monomorphic loci likely reflecting a historical population decline. This illustrates that patterns of genetic diversity should be seen in the context of population histories and that future management decisions should take these insights into account. To address the conservation implications of our findings, we recommend prioritizing the maintenance of suitable habitats to facilitate population connectivity. Initiation of genetic restoration efforts and separately managing populations with unique evolutionary histories is crucial for preserving genetic diversity and promoting long‐term population viability. [ABSTRACT FROM AUTHOR]

Most pathogens are generalists capable of infecting multiple host species or strains. Trade‐offs in performance among different hosts are expected to limit the evolution of generalism. Despite the commonness of generalism, the variation in infectivity, transmission, and trade‐offs in performance among host species have rarely been studied in the wild. To understand the ecological and evolutionary drivers of multi‐host pathogen infectivity and transmission potential, I studied disease severity, transmission dynamics, and infectivity variation of downy mildew pathogen Peronospora sparsa on its three host plants Rubus arcticus, R. chamaemorus, and R. saxatilis. In a survey of 20 wild and cultivated sites of the three host species, disease severity varied by host species and by host population size but not among wild and cultivated sites. To understand how alternative host presence and plant diversity affect transmission of the pathogen, I conducted a transmission experiment. In this experiment, alternative host abundance and plant diversity together modified P. sparsa transmission to trap plants. To understand how resistance to P. sparsa varies among host species and genotypes, I conducted an inoculation experiment using 10 P. sparsa strains from different locations and 20 genotypes of the three host species. Significant variation in infectivity was found among host genotypes but not among host species. When trade‐offs for infectivity were tested, high infectivity in one host species correlated with high infectivity in another host species. However, when pathogen transmission‐related life‐history correlations were tested, a positive correlation was found in R. arcticus but not in R. saxatilis. The results suggest that host resistance may shape pathogen life‐history evolution with epidemiological consequences in a multi‐host pathogen. [ABSTRACT FROM AUTHOR]

Populations composed of individuals descended from multiple distinct genetic lineages often feature significant differences in phenotypic frequencies. We considered hatchery production of steelhead, the migratory anadromous form of the salmonid species Oncorhynchus mykiss, and investigated how differences among genetic lineages and environmental variation impacted life history traits. We genotyped 23,670 steelhead returning to the four California Central Valley hatcheries over 9 years from 2011 to 2019, confidently assigning parentage to 13,576 individuals to determine age and date of spawning and rates of iteroparity and repeat spawning within each year. We found steelhead from different genetic lineages showed significant differences in adult life history traits despite inhabiting similar environments. Differences between coastal and Central Valley steelhead lineages contributed to significant differences in age at return, timing of spawning, and rates of iteroparity among programs. In addition, adaptive genomic variation associated with life history development in this species varied among hatchery programs and was associated with the age of steelhead spawners only in the coastal lineage population. Environmental variation likely contributed to variations in phenotypic patterns observed over time, as our study period spanned both a marine heatwave and a serious drought in California. Our results highlight evidence of a strong genetic component underlying known phenotypic differences in life history traits between two steelhead lineages. [ABSTRACT FROM AUTHOR]

Modern fisheries management strives to balance opposing goals of protection for weak stocks and opportunity for harvesting healthy stocks. Test fisheries can aid management of anadromous fishes if they can forecast the strength and timing of an annual run with adequate time to allow fisheries planning. Integration of genetic stock identification (GSI) can further maximize utility of test fisheries by resolving run forecasts into weak‐ and healthy‐stock subcomponents. Using 5 years (2017–2022) of test fishery data, our study evaluated accuracy, resolution, and lead time of predictions for stock‐specific run timing and abundance of Columbia River spring Chinook salmon (Oncorhynchus tshawytscha). We determined if this test fishery (1) could use visual stock identification (VSI) to forecast at the coarse stock resolution (i.e., classification of "lower" vs. "upriver" stocks) upon which current management is based and (2) could be enhanced with GSI to forecast at higher stock resolution. VSI accurately identified coarse stocks (83.3% GSI concordance), and estimated a proxy for abundance (catch per unit effort, CPUE) of the upriver stock in the test fishery that was correlated (R2 = 0.90) with spring Chinook salmon abundance at Bonneville dam (Rkm 235). Salmon travel rates (~8.6 Rkm/day) provided predictions with 2‐week lead time prior to dam passage. Importantly, GSI resolved this predictive ability as finely as the hatchery broodstock level. Lower river stock CPUE in the test fishery was correlated with abundance at Willamette Falls (Rkm 196, R2 = 0.62), but could not be as finely resolved as achieved for upriver stocks. We described steps to combine VSI and GSI to provide timely in‐season information and with prediction accuracy of ~12.4 mean absolute percentage error and high stock resolution to help plan Columbia River mainstem fisheries. [ABSTRACT FROM AUTHOR]

Most species will not be able to migrate fast enough to cope with climate change, nor evolve quickly enough with current levels of genetic variation. Exacerbating the problem are anthropogenic influences on adaptive potential, including the prevention of gene flow through habitat fragmentation and the erosion of genetic diversity in small, bottlenecked populations. Facilitated adaptation, or assisted evolution, offers a way to augment adaptive genetic variation via artificial selection, induced hybridization, or genetic engineering. One key source of genetic variation, particularly for climatic adaptation, are the core metabolic genes encoded by the mitochondrial genome. These genes influence environmental tolerance to heat, drought, and hypoxia, but must interact intimately and co‐evolve with a suite of important nuclear genes. These coadapted mitonuclear genes form some of the important reproductive barriers between species. Mitochondrial genomes can and do introgress between species in an adaptive manner, and they may co‐introgress with nuclear genes important for maintaining mitonuclear compatibility. Managers should consider the relevance of mitonuclear genetic variability in conservation decision‐making, including as a tool for facilitating adaptation. I propose a novel technique dubbed Conservation Mitonuclear Replacement (CmNR), which entails replacing the core metabolic machinery of a threatened species—the mitochondrial genome and key nuclear loci—with those from a closely related species or a divergent population, which may be better‐adapted to climatic changes or carry a lower genetic load. The most feasible route to CmNR is to combine CRISPR‐based nuclear genetic editing with mitochondrial replacement and assisted reproductive technologies. This method preserves much of an organism's phenotype and could allow populations to persist in the wild when no other suitable conservation options exist. The technique could be particularly important on mountaintops, where rising temperatures threaten an alarming number of species with almost certain extinction in the next century. [ABSTRACT FROM AUTHOR]

While Atlantic salmon (Salmo salar) of the northernmost American populations is alimentary, economically, and culturally important for Ungava Inuit communities (Nunavik, Canada) and might play a key role in the persistence of the species in a global warming context, many mysteries remain about those remote and atypical populations. Thus, our first aim was to document the genomic structure of the Nunavik populations. The second objective was to determine whether salmon only migrating to the estuary without reaching the sea, apparently unique to those populations, represent distinct populations from the typical anadromous salmons and subsequently explore the genetic basis of migratory life‐history tactics in the species. Finally, the third goal was to quantify the contribution of each genetically distinct population and life‐history tactic in the mixed‐stock subsistence fishery of the Koksoak R. estuary. We used Genotyping‐by‐Sequencing to genotype 14,061 single nucleotide polymorphisms in the genome of 248 individuals from 8 source populations and 280 individuals from the Koksoak estuary mixed‐stock fishery. Life‐history tactics were identified by a visual assessment of scales. Results show a hierarchical structure mainly influenced by isolation‐by‐distance with 7 populations out of the 8 studied rivers. While no obvious structure was detected between marine and estuarine salmon within the population, we have identified genomic regions putatively associated with those migration tactics. Finally, all salmon captured in the Koksoak estuary originated from the Koksoak drainage and mostly from 2 tributaries, but no inter‐annual variation in the contribution of these tributaries was found. Our results indicate, however, that both marine and estuarine salmon contribute substantially to estuarine fisheries and that there is inter‐annual variation in this contribution. These findings provide crucial information for the conservation of salmon populations in a rapidly changing ecosystem, as well as for fishery management to improve the food security of Inuit communities. [ABSTRACT FROM AUTHOR]

Understanding how growth and reproduction will adapt to changing environmental conditions is a fundamental question in evolutionary ecology, but predicting the responses of specific taxa is challenging. Analyses of the physiological effects of climate change upon life history evolution rarely consider alternative hypothesized mechanisms, such as size‐dependent foraging and the risk of predation, simultaneously shaping optimal growth patterns. To test for interactions between these mechanisms, we embedded a state‐dependent energetic model in an ecosystem size‐spectrum to ask whether prey availability (foraging) and risk of predation experienced by individual fish can explain observed diversity in life histories of fishes. We found that asymptotic growth emerged from size‐based foraging and reproductive and mortality patterns in the context of ecosystem food web interactions. While more productive ecosystems led to larger body sizes, the effects of temperature on metabolic costs had only small effects on size. To validate our model, we ran it for abiotic scenarios corresponding to the ecological lifestyles of three tuna species, considering environments that included seasonal variation in temperature. We successfully predicted realistic patterns of growth, reproduction, and mortality of all three tuna species. We found that individuals grew larger when environmental conditions varied seasonally, and spawning was restricted to part of the year (corresponding to their migration from temperate to tropical waters). Growing larger was advantageous because foraging and spawning opportunities were seasonally constrained. This mechanism could explain the evolution of gigantism in temperate tunas. Our approach addresses variation in food availability and individual risk as well as metabolic processes and offers a promising approach to understand fish life‐history responses to changing ocean conditions. [ABSTRACT FROM AUTHOR]

As Pacific salmon (Oncorhynchus spp.) decline across much of their range, it is imperative to further develop minimally invasive tools to quantify population abundance. One such advancement, trans‐generational genetic mark–recapture (tGMR), uses parentage analysis to estimate the size of wild populations. Our study examined the precision and accuracy of tGMR through a comparison to a traditional mark–recapture estimate for Chilkat River Chinook salmon (O. tshawytscha) in Southeast Alaska. We examined how adult sampling location and timing impact tGMR by comparing estimates derived using samples collected in the lower river mainstem to those using samples obtained in upriver spawning tributaries. Results indicated that tGMR estimates using a representative sample of mainstem adults were most concordant with, and 3% more precise than, the traditional mark–recapture estimate for this stock. Importantly, the timing and location of adult sampling were found to impact abundance estimates, depending on what proportion of the population dies or moves to unsampled areas between downriver and upriver sampling events. Additionally, we identified potential sources of bias in tGMR arising from violations of key assumptions using a novel individual‐based modeling framework, parameterized with empirical values from the Chilkat River. Simulations demonstrated that increased reproductive success and sampling selectivity of older, larger individuals, introduced negative bias into tGMR estimates. Our individual‐based model offers a customizable and accessible method to identify and quantify these biases in tGMR applications (https://github.com/swrosenbaum/tGMR%5fsimulations). We underscore the critical role of system‐specific sampling design considerations in ensuring the precision and accuracy of tGMR projects. This study validates tGMR as a potentially useful tool for improved population enumeration in semelparous species. [ABSTRACT FROM AUTHOR]

Molecular mechanisms driving the escalation of pyrethroid resistance in the major malaria mosquitoes of Central Africa remain largely uncharacterized, hindering effective management strategies. Here, resistance intensity and the molecular mechanisms driving it were investigated in a population of Anopheles coluzzii from northern Cameroon. High levels of pyrethroid and organochloride resistance were observed in An. coluzzii population, with no mortality for 1× permethrin; only 11% and 33% mortalities for 5× and 10× permethrin diagnostic concentrations, and <2% mortalities for deltamethrin and DDT, respectively. Moderate bendiocarb resistance (88% mortality) and full susceptibility to malathion were observed. Synergist bioassays with piperonyl butoxide recovered permethrin susceptibility, with mortalities increasing to 53.39%, and 87.30% for 5× and 10× permethrin, respectively, implicating P450 monooxygenases. Synergist bioassays with diethyl maleate (DEM) recovered permethrin and DDT susceptibilities (mortalities increasing to 34.75% and 14.88%, respectively), implicating glutathione S‐transferases. RNA‐seq‐based genome‐wide transcriptional analyses supported by quantitative PCR identified glutathione S‐transferase, GSTe2 (RNA‐seqFC = 2.93 and qRT‐PCRFC = 8.4, p < 0.0043) and CYP450, CYP6Z2 (RNA‐seqFC = 2.39 and qRT‐PCRFC = 11.7, p < 0.0177) as the most overexpressed detoxification genes in the pyrethroid‐resistant mosquitoes, compared to mosquitoes of the susceptible Ngousso colony. Other overexpressed genes include P450s, CYP6M2 (FC = 1.68, p < 0.0114), CYP4G16 (FC = 2.02, p < 0.0005), and CYP4G17 (FC = 1.86, p < 0.0276). While high frequency of the 1014F kdr mutation (50%) and low frequencies of 1014S (6.61%) and 1575Y (10.29%) were observed, no ace‐1 mutation was detected in bendiocarb‐resistant populations, suggesting the preeminent role of metabolic mechanism. Overexpression of metabolic resistance genes (including GSTe2 and CYP6Z2 known to confer resistance to multiple insecticides) in An. coluzzii from the Sudan Savannah of Cameroon highlights the need for alternative management strategies to reduce malaria burden in northern Cameroon. [ABSTRACT FROM AUTHOR]

Abstract Recent developments within the IUCN and the Convention on Biological Diversity have affirmed the increasingly key role that effective population size (Ne) and the effective size: census size ratio (Ne/N) play in applied conservation and management of global biodiversity. This paper reviews and synthesizes information regarding the definition of Ne and demographic and genetic methods for estimating effective size, census size, and their ratio. Emphasis is on single‐generation estimates of contemporary Ne/N, which are the most informative for practical applications. It is crucial to clearly define which individuals are included in the census size (N). Defining N as the number of adults alive at a given time facilitates comparisons across species. For a wide range of applications and experimental designs, inbreeding Ne is simpler to calculate and interpret than variance Ne. Effects of skewed sex ratio are generally modest, so most reductions to Ne/N arise from overdispersed (greater‐than‐Poisson) variance in offspring number (σk2). Even when fecundity changes with age, overdispersed within‐age variance generally contributes most to overall σk2, and both random and deterministic (mediated by selection) factors can be important. Most species are age‐structured, so it is important to distinguish between effective size per generation (Ne) and the effective number of breeders in one season or year (Nb). Both Ne and Nb are important for applied conservation and management. For iteroparous species, a key metric is variance in lifetime reproductive success (σk•2), which can be affected by a variety of additional factors, including variation in longevity, skip or intermittent breeding, and persistent individual differences in reproductive success. Additional factors that can be important for some species are also discussed, including mating systems, population structure, sex reversal, reproductive compensation, captive propagation, and delayed maturity.

The successes of introduced populations in novel habitats often provide powerful examples of evolution and adaptation. In the 1950s, opossum shrimp (Mysis diluviana) individuals from Clearwater Lake in Minnesota, USA were transported and introduced to Twin Lakes in Colorado, USA by fisheries managers to supplement food sources for trout. Mysis were subsequently introduced from Twin Lakes into numerous lakes throughout Colorado. Because managers kept detailed records of the timing of the introductions, we had the opportunity to test for evolutionary divergence within a known time interval. Here, we used reduced representation genomic data to investigate patterns of genetic diversity, test for genetic divergence between populations, and for evidence of adaptive evolution within the introduced populations in Colorado. We found very low levels of genetic diversity across all populations, with evidence for some genetic divergence between the Minnesota source population and the introduced populations in Colorado. There was little differentiation among the Colorado populations, consistent with the known provenance of a single founding population, with the exception of the population from Gross Reservoir, Colorado. Demographic modeling suggests that at least one undocumented introduction from an unknown source population hybridized with the population in Gross Reservoir. Despite the overall low genetic diversity we observed, FST outlier and environmental association analyses identified multiple loci exhibiting signatures of selection and adaptive variation related to elevation and lake depth. The success of introduced species is thought to be limited by genetic variation, but our results imply that populations with limited genetic variation can become established in a wide range of novel environments. From an applied perspective, the observed patterns of divergence between populations suggest that genetic analysis can be a useful forensic tool to determine likely sources of invasive species. [ABSTRACT FROM AUTHOR]

Populations of Eurasian otters Lutra lutra, one of the most widely distributed apex predators in Eurasia, have been depleted mainly since the 1950s. However, a lack of information about their genomic diversity and how they are organized geographically in East Asia severely impedes our ability to monitor and conserve them in particular management units. Here, we re‐sequenced and analyzed 20 otter genomes spanning continental East Asia, including a population at Kinmen, a small island off the Fujian coast, China. The otters form three genetic clusters (one of L. l. lutra in the north and two of L. l. chinensis in the south), which have diverged in the Holocene. These three clusters should be recognized as three conservation management units to monitor and manage independently. The heterozygosity of the East Asian otters is as low as that of the threatened carnivores sequenced. Historical effective population size trajectories inferred from genomic variations suggest that their low genomic diversity could be partially attributed to changes in the climate since the mid‐Pleistocene and anthropogenic intervention since the Holocene. However, no evidence of genetic erosion, mutation load, or high level of inbreeding was detected in the presumably isolated Kinmen Island population. Any future in situ conservation efforts should consider this information for the conservation management units. [ABSTRACT FROM AUTHOR]

Resistant cultivars are of value for protecting crops from disease, but can be rapidly overcome by pathogens. Several strategies have been proposed to delay pathogen adaptation (evolutionary control), while maintaining effective protection (epidemiological control). Resistance genes can be (i) combined in the same cultivar (pyramiding), (ii) deployed in different cultivars sown in the same field (mixtures) or in different fields (mosaics), or (iii) alternated over time (rotations). The outcomes of these strategies have been investigated principally in pathogens displaying pure clonal reproduction, but many pathogens have at least one sexual event in their annual life cycles. Sexual reproduction may promote the emergence of superpathogens adapted to all the resistance genes deployed. Here, we improved the spatially explicit stochastic model landsepi to include pathogen sexual reproduction, and we used the improved model to investigate the effect of sexual reproduction on evolutionary and epidemiological outcomes across deployment strategies for two major resistance genes. Sexual reproduction favours the establishment of a superpathogen when single mutant pathogens are present together at a sufficiently high frequency, as in mosaic and mixture strategies. However, sexual reproduction did not affect the strategy recommendations for a wide range of mutation probabilities, associated fitness costs, and landscape organisations. [ABSTRACT FROM AUTHOR]

Recent developments within the IUCN and the Convention on Biological Diversity have affirmed the increasingly key role that effective population size ( N e ) and the effective size: census size ratio ( N ) play in applied conservation and management of global biodiversity. This paper reviews and synthesizes information regarding the definition of e / N ) play in applied conservation and management of global biodiversity. This paper reviews and synthesizes information regarding the definition of N e and demographic and genetic methods for estimating effective size, census size, and their ratio. Emphasis is on single-generation estimates of contemporary N e / N , which are the most informative for practical applications. It is crucial to clearly define which individuals are included in the census size ( N ). Defining N as the number of adults alive at a given time facilitates comparisons across species. For a wide range of applications and experimental designs, inbreeding N e is simpler to calculate and interpret than variance N e . Effects of skewed sex ratio are generally modest, so most reductions to N e / N arise from overdispersed (greater-than-Poisson) variance in offspring number ( σ k 2 ). Even when fecundity changes with age, overdispersed within-age variance generally contributes most to overall σ k 2 , and both random and deterministic (mediated by selection) factors can be important. Most species are age-structured, so it is important to distinguish between effective size per generation ( N e ) and the effective number of breeders in one season or year ( N b ). Both N e and N b are important for applied conservation and management. For iteroparous species, a key metric is variance in lifetime reproductive success ( σ k • 2 ), which can be affected by a variety of additional factors, including variation in longevity, skip or intermittent breeding, and persistent individual differences in reproductive success. Additional factors that can be important for some species are also discussed, including mating systems, population structure, sex reversal, reproductive compensation, captive propagation, and delayed maturity., Competing Interests: The author declares no conflict of interest., (© 2024 The Authors. Evolutionary Applications published by John Wiley & Sons Ltd.)