Strict endosymbiont bacteria with high degree of genome reduction retain smaller proteins and, in certain cases, lack complete functional domains compared to their free-living counterparts. Until now, the mechanisms underlying these genetic reductions are not well understood. However, it is thought that, in order to compensate for gene reduction, somehow hosts take over those vital functions that endosymbionts cannot perform. In the present study, the conservation of RNA polymerases, the essential...
Mon Sep 07, 2020 03:00
Founder events play a critical role in shaping genetic diversity, impacting the fitness of a species and disease risk in humans. Yet our understanding of the prevalence and distribution of founder events in humans and other species remains incomplete, as most existing methods for characterizing founder events require large sample sizes or phased genomes. To learn about the frequency and evolutionary history of founder events, we introduce ASCEND (Allele Sharing Correlation for the Estimation of Non-equilibrium...
Mon Sep 07, 2020 03:00
Colouration plays a key role in the ecology of many species, influencing how an organism interacts with its environment, other species and conspecifics. Guppies are sexually dimorphic, with males displaying sexually selected colouration resulting from female preference. Previous work has suggested that much of guppy colour pattern variation is Y-linked. However, it remains unclear how many individual colour patterns are Y-linked in natural populations as much of the previous work has focused on phenotypes...
Mon Sep 07, 2020 03:00
In previous papers in this series, I described the evolutionary genetic species concept which is based on population genetic theory and should be applicable to any organism. I also described a species criterion, the K/{theta} ratio, that delimits independently evolving evolutionary species based on single-gene sequences. I then illustrated its application to sexual and asexual eukaryotes. Here, I show how the evolutionary genetic species concept and the K/{theta} ratio can be applied to bacteria,...
Mon Sep 07, 2020 03:00
Domestication involves recent adaptation under strong human selection and rapid diversification, and therefore constitutes a good model for studies of these processes. We studied the domestication of the emblematic white mold Penicillium camemberti, used for the maturation of soft cheeses, such as Camembert and Brie, about which surprisingly little was known, despite its economic and cultural importance. Whole genome-based analyses of genetic relationships and diversity revealed that an ancient domestication...
Mon Sep 07, 2020 03:00
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...
Mon Sep 07, 2020 03:00
Comparative genomics has contributed to the growing evidence that sexual selection is an important component of evolutionary divergence and speciation. Divergence by sexual selection is implicated in faster rates of divergence of the X chromosome and of genes thought to underlie sexually selected traits, including genes that are sex-biased in expression. However, accurately inferring the relative importance of complex and interacting forms of natural selection, demography and neutral processes which...
Mon Sep 07, 2020 03:00
Hmx gene conservation identifies the evolutionary origin of vertebrate cranial ganglia [NEW RESULTS]
The evolutionary origin of vertebrates included innovations in sensory processing associated with the acquisition of a predatory lifestyle. Vertebrates perceive external stimuli through sensory systems serviced by cranial sensory ganglia (CSG) which develop from cranial placodes; however understanding the evolutionary origin of placodes and CSGs is hampered by the gulf between living lineages and difficulty in assigning homology between cell types and structures. Here we use the Hmx gene family to...
Mon Sep 07, 2020 03:00
The rate at which plants grow is a major functional trait in plant ecology. However, little is known about its evolution in natural populations. Here, we investigate evolutionary and environmental factors shaping variation in the growth rate of Arabidopsis thaliana. We used plant diameter as a proxy to monitor plant growth over time in environments that mimicked latitudinal differences in the intensity of natural light radiation, across a set of 278 genotypes sampled within four broad regions, including...
Mon Sep 07, 2020 03:00
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