Sex chromosomes are typically comprised of a non-recombining region and a recombining pseudoautosomal region. Accurately quantifying the relative size of these regions is critical for sex chromosome biology both from a functional (i.e. number of sex-linked genes) and evolutionary perspective (i.e. extent of Y degeneration and X-Y heteromorphy). The evolution of the pseudoautosomal boundary (PAB) - the limit between the recombining and the non-recombining regions of the sex chromosomes - is well documented...
Thu Aug 27, 2020 03:00
Gene drives offer the possibility of altering and even suppressing wild populations of countless plant and animal species, and CRISPR technology now provides the technical feasibility of engineering them. However, population-suppression gene drives are prone to select resistance, should it arise. Here we develop mathematical and computational models to identify conditions under which suppression drives will evade resistance, even if resistance is present initially. We show that linkage between the...
Thu Aug 27, 2020 03:00
Although protocols exist for the recovery of ancient DNA from land snail and marine bivalve shells, marine conch shells have yet to be studied from a paleogenomic perspective. We first present reference assemblies for both a 623.7 Mbp nuclear genome and a 15.4 kbp mitochondrial genome for Strombus pugilis, the West Indian fighting conch. We next detail a method to extract and sequence DNA from conch shells and apply it to conch from Bocas del Toro, Panama across three time periods: recently-eaten...
Thu Aug 27, 2020 03:00
The phenomenon of X chromosome inactivation (XCI) mediated by sex-specific differences in DNA methylation is well characterized in eutherian mammals. Although XCI is shared between eutherians and marsupials, the role of marsupial DNA methylation in this process remains contested. Here we examine genome-wide signatures of DNA methylation from methylation maps across fives tissues from a male and female koala (Phascolarctos cinereus) and present the first whole genome, multi-tissue marsupial "methylome...
Thu Aug 27, 2020 03:00
The exceptional species-richness associated with mountains worldwide is linked to the fragmented topography of these areas, responsible for constantly isolating populations during periods of climatic fluctuations. Consequently, endemism and spatial turnover in mountains are very high and few species are widespread among entire mountain ranges, precluding population-level studies that help understanding how macroevolutionary patterns were shaped. Here, we used the bromeliad Vriesea oligantha, a species...
Thu Aug 27, 2020 03:00
Genome sizes vary by orders of magnitude across the Tree of Life and lack any correlation with organismal complexity. Some crustacean orders, such as amphipods, have genome sizes that correlate with body size, temperature, and water depth, indicating that natural selection may constrain genome sizes due to physiological pressures. In this study, we examine the relationship between genome size, repetitive content, and environmental variables on a clade of sand-burrowing amphipods (Haustoriidae) that...
Thu Aug 27, 2020 03:00
Sex differences in lifespan and aging are widespread among animals, with males usually the shorter-lived sex. Despite extensive research interest, it is unclear how lifespan differences between the sexes are modulated by genetic, environmental and social factors. We combined comparative data from natural populations of annual killifishes with experimental results on replicated captive populations, showing that females consistently outlived males in the wild. This sex-specific survival difference...
Thu Aug 27, 2020 03:00
In many species that fight over resources, individuals use specialized structures to overpower their rivals (i.e. weapons). Despite their similar roles for contest settlement (i.e. affecting the winning chances), weapons are highly diverse morphological structures across species. However, the comprehension on how this diversity evolved is still open for debate. Unfortunately, most studies on how weapons are used during contests focus on size asymmetries between winners and losers. Although such information...
Thu Aug 27, 2020 03:00
Whole genome duplication (WGD) events have played a major role in eukaryotic genome evolution, but the consequence of these extreme events in adaptive genome evolution is still not well understood. To address this knowledge gap we used a comparative phylogenetic model and transcriptomic data from seven species to infer selection on gene expression in duplicated genes (ohnologs) following the salmonid WGD 80-100 million years ago. We find rare cases of tissue-specific expression evolution but pervasive...
Thu Aug 27, 2020 03:00
The relationship between embryonic development and evolution historically investigated based on embryo morphology, could now be reassessed using mRNA expression endophenotype. Here, we investigated the applicability of von Baers and Haeckels arguments at mRNA expression level by comparing the developmental changes among nine evolutionarily distinct species: from oyster to mouse. In agreement with models based on von Baers postulates, up to 36% of mRNA expression indicated nearly linear conservation...
Thu Aug 27, 2020 03:00
Body pigmentation is an evolutionarily diversified and ecologically relevant trait that shows variation within and between species, and important roles in animal survival and reproduction. Insect pigmentation, in particular, provides some of the most compelling examples of adaptive evolution and its ecological and genetic bases. Yet, while pigmentation includes multiple aspects of color and color pattern that may vary more or less independently, its study frequently focuses on one single aspect....
Thu Aug 27, 2020 03:00
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