Search

Feralization is the process of domesticated animals returning to the wild and it is considered the counterpart of domestication. Molecular genetic changes are well documented in domesticated organisms but understudied in feral populations. In this study, the genetic differentiation between domestic and feral cats was inferred by analysing whole-genome sequencing data of two geographically distant feral cat island populations, Dirk Hartog Island (Australia) and Kaho'olawe (Hawaii) as well as domestic cats and European wildcats. The study investigated population structure, genetic differentiation, genetic diversity, highly differentiated genes, and recombination rates. Genetic structure analyses linked both feral cat populations to North American domestic and European cat populations. Recombination rates in feral cats were lower than in domestic cats but higher than in wildcats. For Australian and Hawaiian feral cats, 105 and 94 highly differentiated genes compared to domestic cats respectively, were identified. Annotated genes had similar functions, with almost 30% of the divergent genes related to nervous system development in both feral groups. Twenty mutually highly differentiated genes were found in both feral populations. Evolution of highly differentiated genes was likely driven by specific demographic histories, the relaxation of the selective pressures associated with domestication, and adaptation to novel environments to a minor extent. Random drift was the prevailing force driving highly divergent regions, with relaxed selection in feral populations also playing a significant role in differentiation from domestic cats. The study demonstrates that feralization is an independent process that brings feral cats on a unique evolutionary trajectory. [ABSTRACT FROM AUTHOR]

Aim: The Progression Rule, that older lineages inhabit older islands and colonize newer ones as they emerge, has seldom been tested in the Caribbean due to its geological complexity. Here, we use the conifer genus Podocarpus to explore this hypothesis. We infer the evolutionary history, biogeography, and diversification rates of this genus under a hypothesis testing framework. Location: The Caribbean archipelago (Antilles). Taxon: Podocarpus (Podocarpaceae). Methods: We present the most comprehensive sampling for Caribbean Podocarpus to date in a Bayesian dated phylogenetic tree using a genotyping by sequencing DNA matrix of 67,589 bp. We inferred ancestral ranges and inter‐island divergence patterns using several models available. We explored diversification rates associated with island colonization, and checked for diversification rate shifts in the phylogeny. Results: Caribbean Podocarpus is the result of colonization from the Andes during the Eocene to Oligocene (c. 45–31 Ma). Lesser Antillean species originated during the Oligocene from the Andes or the Greater Antilles, depending on the model of choice. Vicariance can explain the divergence of Cuban and Hispaniolan species, with subsequent dispersals into Jamaica. Despite the availability of new habitat opportunities, which might promote cladogenesis, insular Podocarpus did not show higher diversification rates than continental taxa. Main conclusions: The conditions for progression rule were not met because colonization of younger islands (Lesser Antilles) occurred from the continent, or because suitable habitat in the partially emerged younger islands was likely present at the time older islands (Greater Antilles) were colonized. An improved palaeogeographical knowledge of the Caribbean will allow testing this hypothesis in multiple lineages. Our finding that diversification rates did not increase with island colonization might be common in other Caribbean lineages. Genotyping by sequencing proved promising to reveal complex historical assembly processes of vicariance and dispersal at a fine phylogenetic scale. [ABSTRACT FROM AUTHOR]

The Caribbean archipelago is a region with an extremely complex geological history and an outstanding plant diversity with high levels of endemism. The aim of this study was to better understand the historical assembly and evolution of endemic seed plant genera in the Caribbean, by first determining divergence times of endemic genera to test whether the hypothesized Greater Antilles and Aves Ridge ( GAARlandia) land bridge played a role in the archipelago colonization and second by testing South America as the main colonization source as expected by the position of landmasses and recent evidence of an asymmetrical biotic interchange. We reconstructed a dated molecular phylogenetic tree for 625 seed plants including 32 Caribbean endemic genera using Bayesian inference and ten calibrations. To estimate the geographic range of the ancestors of endemic genera, we performed a model selection between a null and two complex biogeographic models that included timeframes based on geological information, dispersal probabilities, and directionality among regions. Crown ages for endemic genera ranged from Early Eocene (53.1 Ma) to Late Pliocene (3.4 Ma). Confidence intervals for divergence times (crown and/or stem ages) of 22 endemic genera occurred within the GAARlandia time frame. Contrary to expectations, the Antilles appears as the main ancestral area for endemic seed plant genera and only five genera had a South American origin. In contrast to patterns shown for vertebrates and other organisms and based on our sampling, we conclude that GAARlandia did not act as a colonization route for plants between South America and the Antilles. Further studies on Caribbean plant dispersal at the species and population levels will be required to reveal finer-scale biogeographic patterns and mechanisms. [ABSTRACT FROM AUTHOR]