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This Week in PNAS: Apr 22, 2014

In one of several domestication-focused articles slated to appear in the same issue of the Proceedings of the National Academy of Sciences, researchers from the UK, Sweden, and Germany turned to ancient chicken sequences to scrutinize potential contributors to domestication. Using DNA from 80 ancient chicken representatives from the 18th century back to nearly 300 years before the common era whose remains were found at a dozen archeological sites in Europe, the researchers looked a handful of genomic loci with proposed ties to domestication, revealing that at least one suspected domestication locus has primarily undergone changes only in the last few hundred years. "[B]y determining genetic variability in ancient European chickens over the past 2,000 years, we show that a mutation thought to be crucial during chicken domestication was not subject to strong human-mediated selection until much later in time," they write.

An international team led by investigators from the Sanger Institute used genome sequences from more than 200 Yersinia strains in an effort to understand the evolution of pathogenicity in that bacterial genus, which includes species that caused diarrheal disease and plague. Results from the researchers' analyses indicated that virulence factors have arisen several times in parallel in pathogenic Yersinia bugs, despite the presence of some shared virulence determinants in different species.

The Max Planck Institute for Evolutionary Anthropology's Svante Pääbo and colleagues scrutinized protein-coding sequences from several Neanderthals, using new exome sequences for Neanderthals from Spain and Croatia and existing sequence data for a Siberian Neanderthal. By comparing the Neanderthal exomes to one another and to protein-coding sequences in humans from African, European, and Asian populations, the researchers determined the nature and extent of the protein-coding variation present in Neanderthals. Despite low levels of genetic diversity in Neanderthals, for example, they saw a jump in the proportion of variants expected to alter the amino acid sequences of Neanderthal proteins. The analysis also highlighted variants in that may explain some of the physical differences identified between Neanderthals and modern humans, which appeared to be particularly common in behavior- and pigmentation-related genes.