Despite its amazing biodiversity, the Eastern Mediterranean remains a highly understudied region especially when compared to the Western Mediterranean. Scarcity of such studies restrict our understanding of the processes shaping diversity across the entire Mediterranean. To this end we used a combination of molecular markers and presence/absence data from all species of the Eastern Mediterrranean genus Ricotia collected across its full geographic range to determine historical, ecological and evolutionary...
Tue Sep 01, 2020 03:00
Humans have undergone large migrations over the past hundreds to thousands of years, exposing ourselves to new environments and selective pressures. Yet, evidence of ongoing or recent selection in humans is difficult to detect. Many of these migrations also resulted in gene flow between previously separated populations. These recently admixed populations provide unique opportunities to study rapid evolution in humans. Developing methods based on distributions of local ancestry, we demonstrate that...
Tue Sep 01, 2020 03:00
Growth plate and articular cartilage constitute a single anatomical entity early in development, but later separate into two distinct structures by the secondary ossification center (SOC). The reason for such separation remains unknown. We found that evolutionarily SOC appears in animals conquering the land - amniotes. Analysis of ossification pattern in mammals with specialized extremities (whales, bats, jerboa) revealed that SOC development correlates with the extent of mechanical loads. Mathematical...
Tue Sep 01, 2020 03:00
Mating systems have profound effects on genetic diversity and compatibility. The convergent evolution of self-fertilization in three Caenorhabditis species provides a powerful lens to examine causes and consequences of mating system transitions. Among the selfers, C. tropicalis is the least genetically diverse and most afflicted by outbreeding depression. We generated a chromosomal-scale genome for C. tropicalis and surveyed global diversity. Population structure is very strong, and islands of extreme...
Tue Sep 01, 2020 03:00
Mutations are the ultimate source of heritable variation and therefore the fuel for evolution, but direct estimates exist only for few species. We estimated the spontaneous nucleotide mutation rate among clonal generations in the waterflea Daphnia galeata with a short term mutation accumulation approach. Individuals from eighteen mutation accumulation lines over five generations were deep genome sequenced to count de novo mutations that were not present in a pool of F1 individuals, representing the...
Tue Sep 01, 2020 03:00
Many familiar traits in the natural world--from lions' manes to the longevity of bristlecone pine trees--arose in the distant past, and have long since fixed in their respective species. A key challenge in evolutionary genetics is to figure out how and why species defining traits have come to be. We used the growth advantage of the yeast Saccharomyces cerevisiae at high temperature, relative to its sister species Saccharomyces paradoxus, as a model for addressing these questions. Starting with a...
Tue Sep 01, 2020 03:00
Sponges are often densely populated by microbes that benefit their hosts through nutrition and bioactive secondary metabolites; however, sponges must simultaneously contend with the toxicity of microbes and thwart microbial overgrowth. Despite these fundamental tenets of sponge biology, the patterns of selection in the host sponge genomes that underlie tolerance and control of their microbiomes are still poorly understood. To elucidate these patterns of selection, we performed a population genetic...
Tue Sep 01, 2020 03:00
Mothers are crucial for mammals' survival before nutritional independence, but many social mammals reside with their mothers long after. In these species the social adversity caused by maternal loss later in life can dramatically reduce fitness. However, in some human populations these negative consequences appear to be overcome by care from other group members. We investigated the consequences of maternal loss in mountain gorillas and found no discernible fitness costs to maternal loss through survival,...
Tue Sep 01, 2020 03:00
Understanding the rate and pattern of germline mutations is of fundamental importance for understanding evolutionary processes. Here we analyzed 19 parent-offspring trios of rhesus macaques (Macaca mulatta) at high sequencing coverage of ca. 76X per individual, and estimated an average rate of 0.77 x 10-8 de novo mutations per site per generation (95 % CI: 0.69 x 10-8 - 0.85 x 10-8). By phasing 50 % of the mutations to parental origins, we found that the mutation rate is positively correlated with...
Tue Sep 01, 2020 03:00
The most fundamental form of epistasis occurs between residues within a protein. Epistatic interactions can have significant consequences for evolutionary dynamics. For example, a substitution to a deleterious amino acid may be compensated for by replacements at other sites which increase its propensity (a function of its average fitness) over time - this is the evolutionary Stokes shift. We discovered that an opposite trend -the decrease in amino acid propensity with time- can also occur via the...
Tue Sep 01, 2020 03:00
Phenotypic plasticity, the ability of an organism to express multiple phenotypes in response to the prevailing environmental conditions without genetic change, may occur as a response to anthropogenic environmental change. Arguably, the most significant future anthropogenic environment change is contemporary climate change. Given that increasing climate variability is predicted to pose a greater risk than directional climate change, we tested the effect of a water temperature differential of 4 degree...
Tue Sep 01, 2020 03:00
In Europe, Puumala virus (PUUV) is responsible for nephropathia epidemica (NE), a mild form of haemorrhagic fever with renal syndrome (HFSR). Despite the presence of its reservoir, the bank vole, on most of French territory, the geographic distribution of NE cases is heterogeneous and NE endemic and non-endemic areas have been reported. In this study we analyzed whether bank vole-PUUV interactions could partly shape these epidemiological differences. We performed crossed-experimental infections using...
Tue Sep 01, 2020 03:00
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