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Understanding the forces that shape population genetic structure is fundamental both for understanding evolutionary trajectories and for conservation. Many factors can influence the geographic distribution of genetic variation, and the extent to which local populations differ can be especially difficult to predict in highly mobile organisms. For example, many species of seabirds are essentially panmictic, but some show strong structure. Pigeon Guillemots (Cepphus columba; Charadriiformes: Alcidae) breed in small colonies scattered along the North Pacific coastline and feed in shallow nearshore waters year‐round. Given their distribution, gene flow is potentially lower and population genetic structure is stronger than in most other high‐latitude Northern Hemisphere seabirds. We screened variation in the mitochondrial control region, four microsatellite loci, and two nuclear introns in 202 Pigeon Guillemots representing three of five subspecies. Mitochondrial sequences and nuclear loci both showed significant population differences, although structure was weaker for the nuclear loci. Genetic differentiation was correlated with geographic distance between sampling locations for both the mitochondrial and nuclear loci. Mitochondrial gene trees and demographic modeling both provided strong evidence for two refugial populations during the Pleistocene glaciations: one in the Aleutian Islands and one farther east and south. We conclude that historical fragmentation combined with a stepping‐stone model of gene flow led to the relatively strong population differentiation in Pigeon Guillemots compared to other high‐latitude Northern Hemisphere seabird species. Our study adds to growing evidence that Pleistocene glaciation events affected population genetic structure not only in terrestrial species but also in coastal marine animals. [ABSTRACT FROM AUTHOR]

Rotations have been the cornerstone of insecticide resistance management for many decades. In recent years, there has been a resurgence of interest in the use of insecticide mixtures, particularly based on new theoretical models. Here, we present a perspective on the value of rotations to insecticide resistance management, focusing on the interpretation of influential theoretical models. The principles of resistance management have previously been reduced to moderation, saturation and multiple attack. Alongside mixtures and mosaics, rotations have been presented as a strategy of multiple attack in using more than one insecticide. Three explanations have been offered for how rotations delay resistance evolution: counterselection from resistance cost, the relaxation of selection and intergenerational redundant kill. We show that all three explanations can make sense of the comparison of rotations with another resistance‐management strategy but have failed to elucidate the principle at work. Overall, we argue that rotations work by moderation, delaying resistance to insecticides through the use of each insecticide less over time. We suggest that the principles of resistance management are recast as moderation, saturation and redundancy. When rotations and mixtures are not conceptualised as competing methods of multiple attack, these strategies can more obviously work together through the complementary principles of moderation and redundancy. Whether solo products or a mixture of products are used, rotations are an effective method of risk management, preserving the arsenal of all effective insecticides for longer. A successful resistance‐management plan should make appropriate use of all the principles of resistance management. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Assortative mating, where individuals non‐randomly mate with respect to phenotype or genotype, can occur when preferences between potential mates have evolved. When such mate preferences occur in a population it can drive evolutionary and phenotypic divergence. But the extent to which assortative mating, mate preference, and development are evolutionarily linked remains unclear. Here we use Streblospio benedicti, a marine annelid with a rare developmental dimorphism, to investigate if mate‐choice could contribute to developmental evolution. For S. benedicti two types of ecologically and phenotypically similar adults persist in natural populations, but they give rise to distinctly different offspring with alternative life‐histories. This dimorphism persists despite the absence of post‐zygotic reproductive barriers, where crosses between the developmental types can produce phenotypically intermediate offspring. How this life‐history strategy evolved remains unknown, but assortative mating is a typical first step in evolutionary divergence. Here we investigate if female mate‐choice is occurring in this species. We find that mate preferences could be contributing to the maintenance of alternative developmental and life‐history strategies. Research highlights: It is rare to find an organism that has two types of development within a species. We use such a system to investigate if mate preference between the developmental types is a possible mechanism to create or reinforce population diversification. [ABSTRACT FROM AUTHOR]

Vertebrate pigmentation patterns are amongst the best characterised model systems for studying the genetic basis of adaptive evolution. The wealth of available data on the genetic basis for pigmentation evolution allows for analysis of trends and quantitative testing of evolutionary hypotheses. We employed Gephebase, a database of genetic variants associated with natural and domesticated trait variation, to examine trends in how cis‐regulatory and coding mutations contribute to vertebrate pigmentation phenotypes, as well as factors that favour one mutation type over the other. We found that studies with lower ascertainment bias identified higher proportions of cis‐regulatory mutations, and that cis‐regulatory mutations were more common amongst animals harbouring a higher number of pigment cell classes. We classified pigmentation traits firstly according to their physiological basis and secondly according to whether they affect colour or pattern, and identified that carotenoid‐based pigmentation and variation in pattern boundaries are preferentially associated with cis‐regulatory change. We also classified genes according to their developmental, cellular, and molecular functions. We found a greater proportion of cis‐regulatory mutations in genes implicated in upstream developmental processes compared to those involved in downstream cellular functions, and that ligands were associated with a higher proportion of cis‐regulatory mutations than their respective receptors. Based on these trends, we discuss future directions for research in vertebrate pigmentation evolution. [ABSTRACT FROM AUTHOR]

There is widespread recognition of the need to increase research opportunities in biomedical science for undergraduate students from underrepresented backgrounds. Here, we describe the implementation of team‐based science combined with intensive mentoring to conduct a large‐scale project examining the evolution of behavior. This system can be widely applied in other areas of STEM to promote research‐intensive opportunities in STEM fields and to promote diversity in science. Highlight: Oliva et al. use course‐based undergraduate research experiences (CURE)‐based methodology for discovery‐oriented science.The structure of the CURE course is scalable with the potential to increase access to research. [ABSTRACT FROM AUTHOR]

The repeated evolution of tetrodotoxin (TTX) resistance provides a model for testing hypotheses about the mechanisms of convergent evolution. This poison is broadly employed as a potent antipredator defence, blocking voltage‐gated sodium channels (Nav) in muscles and nerves, paralysing and sometimes killing predators. Resistance in taxa bearing this neurotoxin and a few predators appears to come from convergent replacements in specific Nav residues that interact with TTX. This stereotyped genetic response suggests molecular and phenotypic evolution may be constrained and predictable. Here, we investigate the extent of mechanistic convergence in garter snakes (Thamnophis) that prey on TTX‐bearing newts (Taricha) by examining the physiological and genetic basis of TTX resistance in the Sierra garter snake (Th. couchii). We characterize variation in this predatory adaptation across populations at several biological scales: whole‐animal TTX resistance; skeletal muscle resistance; functional genetic variation in three Nav encoding loci; and levels of gene expression for one of these loci. We found Th. couchii possess extensive geographical variation in resistance at the whole‐animal and skeletal muscle levels. As in other Thamnophis, resistance at both levels is highly correlated, suggesting convergence across the biological levels linking organism to organ. However, Th. couchii shows no functional variation in Nav loci among populations or difference in candidate gene expression. Local variation in TTX resistance in Th. couchii cannot be explained by the same relationship between genotype and phenotype seen in other taxa. Thus, historical contingencies may lead different species of Thamnophis down alternative routes to local adaptation. [ABSTRACT FROM AUTHOR]

Variation in pelvic morphology has a complex genetic basis and its patterning and specification is governed by conserved developmental pathways. Whether the mechanisms underlying the differentiation and specification of the pelvis also produce the morphological covariation on which natural selection may act, is still an open question in evolutionary developmental biology. We use high‐resolution quantitative trait locus (QTL) mapping in the F34 generation of an advanced intercross experiment (LG,SM‐G34) to characterize the genetic architecture of the mouse pelvis. We test the prediction that genomic features linked to developmental patterning and differentiation of the hind limb and pelvis and the regulation of chondrogenesis are overrepresented in QTL. We find 31 single QTL trait associations at the genome‐ or chromosome‐wise significance level coalescing to 27 pleiotropic loci. We recover further QTL at a more relaxed significance threshold replicating locations found in a previous experiment in an earlier generation of the same population. QTL were more likely than chance to harbor Pitx1 and Sox9 Class II chromatin immunoprecipitation‐seq features active during development of skeletal features. There was weak or no support for the enrichment of seven more categories of developmental features drawn from the literature. Our results suggest that genotypic variation is channeled through a subset of developmental processes involved in the generation of phenotypic variation in the pelvis. This finding indicates that the evolvability of complex traits may be subject to biases not evident from patterns of covariance among morphological features or developmental patterning when either is considered in isolation. Research Highlights: Pelvic variation maps to locations in the genome that are enriched in for Sox9 Class II and Pitx1 features.Few genes previously implicated as playing a core role in the development of the pelvis occur in mapped intervals. [ABSTRACT FROM AUTHOR]

The dietary specialist fruit fly Drosophila sechellia has evolved resistance to the secondary defence compounds produced by the fruit of its host plant, Morinda citrifolia. The primary chemicals that contribute to lethality of M. citrifolia are the medium‐chain fatty acids octanoic acid (OA) and hexanoic acid. At least five genomic regions contribute to this adaptation in D. sechellia and whereas the fine‐mapped major effect locus for OA resistance on chromosome 3R has been thoroughly analysed, the remaining four genomic regions that contribute to toxin resistance remain uncharacterized. To begin to identify the genetic basis of toxin resistance in this species, we removed the function of well‐known detoxification gene families to determine whether they contribute to toxin resistance. Previous work found that evolution of cytochrome P450 enzymatic activity or expression is not responsible for the OA resistance in D. sechellia. Here, we tested the role of the two other major detoxification gene families in resistance to Morinda fruit toxins – glutathione‐S‐transferases and esterases – through the use of the pesticide synergists diethyl maleate and tribufos that inhibit the function of these gene families. This work suggests that one or more esterase(s) contribute to evolved OA resistance in D. sechellia. [ABSTRACT FROM AUTHOR]

Summary: Atlantic salmon (Salmo salar L.) is among the most iconic and economically important fish species and was the first member of Salmonidae to have a high‐quality reference genome assembly published. Advances in genomics have become increasingly central to the genetic improvement of farmed Atlantic salmon as well as conservation of wild salmon stocks. The salmon genome has also been pivotal in shaping our understanding of the evolutionary and functional consequences arising from an ancestral whole‐genome duplication event characterising all Salmonidae members. Here, we provide a review of the current status of Atlantic salmon genetics and genomics, focussed on progress made from genome‐wide research aimed at improving aquaculture production and enhancing understanding of salmonid ecology, physiology and evolution. We present our views on the future direction of salmon genomics, including the role of emerging technologies (e.g. genome editing) in elucidating genetic features that underpin functional variation in traits of commercial and evolutionary importance. [ABSTRACT FROM AUTHOR]

Considerable progress has been made in ecological and evolutionary genetics with studies demonstrating how genes underlying plant and microbial traits can influence adaptation and even 'extend' to influence community structure and ecosystem level processes. Progress in this area is limited to model systems with deep genetic and genomic resources that often have negligible ecological impact or interest. Thus, important linkages between genetic adaptations and their consequences at organismal and ecological scales are often lacking. Here we introduce the Sphagnome Project, which incorporates genomics into a long-running history of Sphagnum research that has documented unparalleled contributions to peatland ecology, carbon sequestration, biogeochemistry, microbiome research, niche construction, and ecosystem engineering. The Sphagnome Project encompasses a genus-level sequencing effort that represents a new type of model system driven not only by genetic tractability, but by ecologically relevant questions and hypotheses. [ABSTRACT FROM AUTHOR]

Evolutionary alterations to cis-regulatory sequences are likely to cause adaptive phenotypic complexity, through orchestrating changes in cellular proliferation, identity and communication. For nonmodel organisms with adaptive key innovations, patterns of regulatory evolution have been predominantly limited to targeted sequence-based analyses. Chromatin immunoprecipitation with high-throughput sequencing (Ch IP-seq) is a technology that has been primarily used in genetic model systems and is a powerful experimental tool to screen for active cis-regulatory elements. Here, we show that it can also be used in ecological model systems and permits genomewide functional exploration of cis-regulatory elements. As a proof of concept, we use Ch IP-seq technology in adult fin tissue of the cichlid fish Oreochromis niloticus to map active promoter elements, as indicated by occupancy of trimethylated Histone H3 Lysine 4 (H3K4me3). The fact that cichlids are one of the most phenotypically diverse and species-rich families of vertebrates could make them a perfect model system for the further in-depth analysis of the evolution of transcriptional regulation. [ABSTRACT FROM AUTHOR]

Rapid adaptation of invasive species to novel habitats has puzzled evolutionary biologists for decades, especially as this often occurs in the face of limited genetic variability. Although some ecological traits common to invasive species have been identified, little is known about the possible genomic/genetic mechanisms that may underlie their success. A common scenario in many introductions is that small founder population sizes will often lead to reduced genetic diversity, but that invading populations experience large environmental perturbations, such as changes in habitat and environmental stress. Although sudden and intense stress is usually considered in a negative context, these perturbations may actually facilitate rapid adaptation by affecting genome structure, organization and function via interactions with transposable elements ( TEs), especially in populations with low genetic diversity. Stress-induced changes in TE activity can alter gene action and can promote structural variation that may facilitate the rapid adaptation observed in new environments. We focus here on the adaptive potential of TEs in relation to invasive species and highlight their role as powerful mutational forces that can rapidly create genetic diversity. We hypothesize that activity of transposable elements can explain rapid adaptation despite low genetic variation (the genetic paradox of invasive species), and provide a framework under which this hypothesis can be tested using recently developed and emerging genomic technologies. [ABSTRACT FROM AUTHOR]

Ciliate nuclear architecture, in particular the sequestration of a transcriptionally silent germline genome, allows for the accumulation of mutations that are 'hidden' from selection during many rounds of asexual reproduction. After sexual conjugation, these mutations are expressed, potentially resulting in highly variable phenotypes. Morphological traits are widely used in ciliate taxonomy, however, the extent to which the values of these traits are robust to change in the face of mutation remains largely unknown. In this study, we examine the effects of mutations accumulated in the germline genome to test the mutational robustness of four traits commonly used in ciliate morphological taxonomy (number of somatic kineties, number of postoral kineties, macronuclear size, and cell size). We found that the number of postoral kineties is robust to mutation, confirming that it should be preferentially used in taxonomy. By contrast, we found that, as in other unicellular and multicellular species, cell and macronucleus sizes change in response to mutation. Thus, we argue that cell and macronucleus sizes, which are widely used in taxonomy, should be treated cautiously for species identification. Finally, we found evidence of correlations between cell and macronucleus sizes and fitness, suggesting possible mutational pleiotropy. This study demonstrates the importance of, and methods for, determining mutational robustness to guide morphological taxonomy in ciliates. [ABSTRACT FROM AUTHOR]

The Illumina Hiseq platform was used to sequence the entire mitochondrial coding-regions of 20 body lice, Pediculus humanus Linnaeus, and head lice, P. capitis De Geer (Phthiraptera: Pediculidae), from eight towns and cities in five countries:Ethiopia, France, China, Australia and the U.S.A. These data (∼310 kb) were used to see how much more informative entire mitochondrial coding-region sequences were than partial mitochondrial coding-region sequences, and thus to guide the design of future studies of the phylogeny, origin, evolution and taxonomy of body lice and head lice. Phylogenies were compared from entire coding-region sequences (∼15.4 kb),entire cox1 (∼1.5 kb), partial cox1 (∼700 bp) and partial cytb (∼600 bp) sequences. On the one hand, phylogenies from entire mitochondrial coding-region sequences (∼15.4 kb) were much more informative than phylogenies from entire cox1 sequences (∼1.5 kb) and partial gene sequences (∼600 to ∼700 bp). For example, 19 branches had >95% bootstrap support in our maximum likelihood tree from the entire mitochondrial coding-regions (∼15.4 kb) whereas the tree from 700 bp cox1 had only two branches with bootstrap support >95%. Yet, by contrast, partial cytb (∼600 bp) and partial cox1 (∼486 bp) sequences were sufficient to genotype lice to Clade A, B or C. The sequences of the mitochondrial genomes of the P. humanus, P. capitis and P. schaeffi Fahrenholz studied are in NCBI GenBank under the accession numbers KC660761-800,KC685631-6330, KC241882-97, EU219988-95, HM241895-8 and JX080388-407. [ABSTRACT FROM AUTHOR]

With 6 figures and 3 tables The present trial assesses the cytoplasmic effects of Brassica napus (AC) and Brassica carinata (BC) on certain characteristics of Brassica rapa (A), Brassica oleracea (C) and Brassica nigra (B). Alloplasmic lines were developed from AC × A, AC × C, BC × B and BC × C hybrids followed by recurrent backcrossing for seven generations. Twenty‐five populations from three generations were compared. The alloplasmic B. oleracea lines with AC‐cytoplasm exhibited the shortest filament length, weakly developed anthers, smaller petal size and more than two stigmas, whereas the alloplasmic B. rapa lines with AC‐cytoplasm were normal; the alloplasmic B. oleracea lines with BC‐cytoplasm formed three groups with short, middle or normal filament length, whereas the alloplasmic B. nigra lines with BC‐cytoplasm were normal. From these results, it was concluded that the cytoplasm effect of AC on C is greater than that on A; BC on C is greater than that on B, further suggesting that the cytoplasm effect of AC on C is greater than that of BC on C. [ABSTRACT FROM AUTHOR]

The article focuses on the evolutionary factors of olfaction and its bioanthropological functions. It states that olfactory receptor genes comprise the largest portion of the genetic make-up of mammals and that genetic differences in olfactory receptors are responsible for variations in cultural perceptions of odors. It also discusses the biological significance of pheromones. Moreover, it tells that disorders in olfaction may lead individuals to have problems regarding obesity and nutrition.

How natural selection on adaptive traits is filtered to the genetic level remains largely unknown. Theory and quantitative trait locus (QTL) mapping have provided insights into the number and effect of genes underlying adaptations, but these results have been hampered by questions of applicability to real biological systems and poor resolution, respectively. Advances in molecular technologies have expedited the cloning of adaptive genes through both forward and reverse genetic approaches. Forward approaches start with adaptive traits and attempt to characterize their underlying genetic architectures through linkage disequilibrium mapping, QTL mapping, and other methods. Reverse screens search large sequence data sets for genes that possess the signature of selection. Though both approaches have been successful in identifying adaptive genes in plants, very few, if any, of these adaptations' molecular bases have been fully resolved. The continued isolation of plant adaptive genes will lead to a more comprehensive understanding of natural selection's effect on genes and genomes. [ABSTRACT FROM AUTHOR]

Abstract Although much is known about the ecological significance of metamorphosis and metamorphic timing, few studies have examined the underlying genetic architecture of these traits, and no study has attempted to associate phenotypic variation to molecular variation in specific genes. Here we report on a candidate gene approach (CGA) to test specific loci for a statistical contribution to variation in metamorphic timing. Three segregating populations (SP1, SP2 and SP3) were constructed utilizing three species of paedomorphic Mexican ambystomatid salamander, including the axolotl, Ambystoma mexicanum . We used these replicated species to test the hypothesis that inheritance of alternate genotypes at two thyroid hormone receptor loci (TRα, TRβ ) affects metamorphic timing in ambystomatid salamanders. A significant TRα *SP effect indicated that variation in metamorphic timing may be influenced by TRα genotype, however, the effect was not a simple one, as both the magnitude and direction of the phenotypic effect depended upon the genetic background. These are the first data to implicate a specific gene in contributing to variation in metamorphic timing. In general, candidate gene approaches can be extended to any number of loci and to any organism where simple genetic crosses can be performed to create segregating populations. The approach is thus of particular value in ecological studies where target genes have been identified but the study organism is not one of the few well-characterized model systems that dominate genetic research. [ABSTRACT FROM AUTHOR]

Abstract In many organisms metamorphosis allows for an ecologically important habitat-shift from water to land. However, in some salamanders an adaptive life cycle mode has evolved that is characterized by metamorphic failure (paedomorphosis); these species remain in the aquatic habitat throughout the life cycle. Perhaps the most famous example of metamorphic failure is the Mexican axolotl (Ambystoma mexicanum), which has become a focal species for developmental biology since it was introduced into laboratory culture in the 1800s. Our previous genetic linkage mapping analysis, using an interspecific crossing design, demonstrated that a major gene effect underlies the expression of metamorphic failure in laboratory stocks of the Mexican axolotl. Here, we repeated this experiment using A. mexicanum that were sampled directly from their natural habitat at Lake Xochimilco, Mexico. We found no significant association between the major gene and metamorphic failure when wild-caught axolotls were used in the experimental design, although there is evidence of a smaller genetic effect. Thus, there appears to be genetic variation among Mexican axolotls (and possibly A. tigrinum tigrinum) at loci that contribute to metamorphic failure. This result suggests a role for more than one mutation and possibly artificial selection in the evolution of the major gene effect in the laboratory Mexican axolotl. [ABSTRACT FROM AUTHOR]

The dynamics and consequences of introgression can inform about numerous evolutionary processes. Biologists have therefore long been interested in hybridization. One challenge, however, lies in the identification of nonadmixed genotypes that can serve as a baseline for accurate quantification of admixture. In this issue of Molecular Ecology, Cahill et al. (2015) analyse a genomic data set of 28 polar bears, eight brown bears and one American black bear. Polar bear alleles are found to be introgressed into brown bears not only near a previously identified admixture zone on the Alaskan Admiralty, Baranof and Chichagof (ABC) Islands, but also far into the North American mainland. Elegantly contrasting admixture levels at autosomal and X chromosomal markers, Cahill and colleagues infer that male-biased dispersal has spread these introgressed alleles away from the Late Pleistocene contact zone. Compared to a previous study on the ABC Island population in which an Alaskan brown bear served as a putatively admixture-free reference, Cahill et al. (2015) utilize a newly sequenced Swedish brown bear as admixture baseline. This approach reveals that brown bears have been impacted by introgression from polar bears to a larger extent (up to 8.8% of their genome), than previously known, including the bear that had previously served as admixture baseline. No evidence for introgression of brown bear into polar bear is found, which the authors argue could be a consequence of selection. Besides adding new exciting pieces to the puzzle of polar/brown bear evolutionary history, the study by Cahill and colleagues highlights that wildlife genomics is moving from analysing single genomes towards a landscape genomics approach. [ABSTRACT FROM AUTHOR]

Tuatara represent the last surviving member of the order Rhynchocephalia, a group of reptiles the members of which first appeared in the fossil record 200 million years ago. We report the existence of extensive minisatellite DNA variation in island populations of tuatara, as revealed by the use of heterologous DNA probes and compare this variation to that found in other vertebrates. Patterns of minisatellite variation within and among populations of tuatara on the Taranga and Marotere Islands off the coast of New Zealand are detailed. Individuals from West Bay and South Cove on Motumuka Island show higher levels of bandsharing than that recorded between randomly sampled individuals from the same island. We suggest that these populations comprise a proportion of closely related individuals and that populations within islands are genetically structured. Moreover, we identified individuals which have high levels of bandsharing with substantial proportions of the sampled population, suggesting close kinship. A pairwise, inter-island comparison of individuals from Mohunuka, Whatupuke and Mauimua Islands, reveals significant differences in distribution of restriction fragments in minisatellite DNA profiles. [ABSTRACT FROM AUTHOR]

An interview with John R. Stinchcombe, a biologist and co-editor of the periodical "New Phytologist," is presented. Stinchcombe shares what inspired him to study plant science. He also talks about his decision to pursue a career in research, his role models in the field and his favorite research papers published in the magazine.