The golden-crowned (Zonotrichia atricapilla) and white-crowned (Z. leucophrys) sparrows have been presented as a compelling case for rapid speciation. They display divergence in song and plumage with overlap in their breeding ranges implying reproductive isolation, but have almost identical mitochondrial genomes. Previous research proposed hybridization and subsequent mitochondrial introgression as an alternate explanation, but lacked robust nuclear gene trees to distinguish between introgression...
Thu Aug 20, 2020 03:00
Male animals are not given equal mating opportunities under competitive circumstances. Small males often exhibit alternative mating behaviours and produce spermatozoa of higher quality to compensate for their lower chances of winning physical contests against larger competitors [1]. Because the reproductive benefits of these phenotypes depend on social status/agonistic ranks that can change during growth or aging [2], sperm traits should be developed/switched into fitness optima according to their...
Thu Aug 20, 2020 03:00
To convey meaning, human language relies on hierarchically organized, long-range relationships spanning words, phrases, sentences, and discourse. The strength of the relationships between sequentially ordered elements of language (e.g., phonemes, characters, words) decays following a power law as a function of sequential distance. To understand the origins of these relationships, we examined long-range statistical structure in the speech of human children at multiple developmental time points, along...
Thu Aug 20, 2020 03:00
Collective behaviors, such as schooling of fishes and mass migrations of ungulates, are hallmark features of a wide variety of animal species. Such phenotypic characters can be lost, either through evolutionary process across generations or by certain environmental stressors within a generation. Such stressors simultaneously promote stereotypic repetitive behaviors in many mammals, such as those exhibited in certain ex-situ captive settings. However, in asocial species, it is unclear whether social...
Thu Aug 20, 2020 03:00
A detailed derivation of the f-statistics formalism is made from a geometrical framework. It is shown that the f-statistics appear when a genetic distance matrix is constrained to describe a four population phylogenetic tree. The choice of genetic metric is crucial and plays an outstanding role as regards the tree-like-ness criterion. The case of lack of treeness is interpreted in the formalism as presence of population admixture. In this respect, four formulas are given to estimate the admixture...
Thu Aug 20, 2020 03:00
Gene duplications contribute to the evolution of biological diversity. The ancestor of the Drosophila Homeodomain (HD) protein Bicoid (AncBcd) emerged after a duplication of a Zerknullt (Zen)-like ancestral protein (AncZB) in a suborder of flies. AncBcd evolved and diverged from AncZB, gaining novel transcriptional and translational activities. Here, we focus on the evolution of the AncBcd HD, which binds DNA and RNA, and is comprised of four subdomains, an N-terminal arm (NT) and three helices:...
Thu Aug 20, 2020 03:00
During range expansion, edge populations are expected to face increased genetic drift, which in turn can alter and potentially compromise adaptive dynamics, preventing the removal of deleterious mutations and slowing down adaptation. Here, we contrast populations of the European sub-species Arabidopsis lyrata ssp petraea, which expanded its Northern range after the last glaciation. We document a sharp decline in effective population size in the range edge population and observe that nonsynonymous...
Thu Aug 20, 2020 03:00
Antibiotic resistance is a growing health concern. Efforts to control resistance would benefit from an improved ability to forecast when and how it will evolve. Epistatic interactions between mutations can promote divergent evolutionary trajectories, which complicates our ability to predict evolution. We recently showed that differences between genetic backgrounds can lead to idiosyncratic responses in the evolvability of phenotypic resistance, even among closely related Escherichia coli strains....
Thu Aug 20, 2020 03:00
The sleeping chironomid Polypedilum vanderplanki is capable of anhydrobiosis, a striking example of adaptation to extreme desiccation. Tolerance to complete desiccation in this species is associated with the emergence of multiple paralogs of protective genes. One of the gene families highly expressed under anhydrobiosis and involved in this process are protein-L-isoaspartate (D-aspartate) O-methyltransferases (PIMTs). Recently, a closely related anhydrobiotic midge from Malawi, P. pembai, showing...
Thu Aug 20, 2020 03:00
Coalescent methods are proven and powerful tools for population genetics, phylogenetics, epidemiology, and other fields. A promising avenue for the analysis of large genomic alignments, which are increasingly common, are coalescent hidden Markov model (coalHMM) methods, but these methods have lacked general usability and flexibility. We introduce a novel method for automatically learning a coalHMM and inferring the posterior distributions of evolutionary parameters using black-box variational inference,...
Thu Aug 20, 2020 03:00
Although much of what we know about the genetic basis of herbicide resistance has come from detailed investigations of monogenic adaptation at known target-sites, the importance of polygenic resistance has been increasingly recognized. Despite this, little work has been done to characterize the genomic basis of herbicide resistance, including the number and distribution of involved genes, their effect sizes, allele frequencies, and signatures of selection. Here we implement genome-wide association...
Thu Aug 20, 2020 03:00
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