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This Week in PNAS: Jan 8, 2019

Editor's Note: Some of the articles described below are not yet available at the PNAS site, but they are scheduled to be posted some time this week.

In a paper set to appear online this week in the Proceedings of the National Academy of Sciences, a New York University-led team profiles virulence evolution and drug resistance in community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) cases that sprung up in Orthodox Jewish children in Brooklyn between spring, 2015 and late 2016. Using medical record reviews, genotyping, genome sequencing, phylogenetics, and comparisons with representatives from the pandemic sequence type USA300, the team documented the evolution of a distinct, highly virulent CA-MRSA clone that emerged in the community, leading to drug-resistant skin infections that appeared to spread with the help of intestinal colonization — findings supported by their subsequent mouse experiments. Together, the authors say, the results suggest that "high-risk populations are incubators for evolution of consequential phenotypes." 

Researchers from the University of Texas and elsewhere describe conserved neural transcriptional features that seem to coincide with monogamy in a range of model organisms. The team compared neural transcriptome features in reproductive males from 10 matched monogamous and non-monogamous species of mice, voles, songbirds, frogs, and fish. Findings from the analysis suggest that "while evolutionary divergence time between species or clades did not explain gene expression similarity, characteristics of the mating system correlated with neural gene expression patterns," the investigators write, "and neural gene expression varied concordantly across vertebrates when species transition to monogamy." They argue that the work "provides evidence of a universal transcriptomic mechanism underlying the evolution of monogamy in vertebrates."

Finally, a team from the US, Turkey, and China characterizes mutations in the Ras signaling-related gene GRAP that contributes to a form of autosomal recessive, non-syndromic sensorineural hearing loss. After tracking down a deafness-associated GRAP variant with exome or genome sequencing on members of two affected families of Turkish ancestry, the researchers profiled GRAP expression, localization, and more in the mouse inner ear and used loss-of-function experiments in Drosophila fruit fly ortholog of the gene to further tease out GRAP's hearing-related role.