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PNAS Papers on Muwekma Ohlone Population, Microbe Evolution in Microchannels, More

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

Researchers at the University of Illinois, Stanford University, and elsewhere share findings from a genomic study of the Muwekma Ohlone Tribe — found to share ancestry with ancient inhabitants of an area that is now in California. The team sequenced a dozen ancient representatives from two San Francisco Bay Area sites, along with eight Indigenous individuals from the contemporary Muwekma Ohlone Tribe. Together with available sequence data from other populations, the new genetic analysis "reaffirms the Muwekma Ohlone's deep-time ties to the area, providing evidence that disagrees with linguistic and archeological reconstructions positing that the Ohlone are late migrants to the region," the authors write, adding that the current findings "have also generated interest from tribal leadership in carrying out similar genomic investigations on ancestral remains from older sites in order to better document and understand the time depth of Ohlone population-genetic continuity in the San Francisco Bay region." GenomeWeb has more on the study, here.

A Japanese team outlines an Escherichia coli population genetic analysis centered on microbes growing and adapting within microchannels. Using experimental testing and theoretical modeling, the researchers tracked genetic diversity, microbial dynamics, organization, and other features in two competing E. coli strains growing in an open-ended microchannel. "Our experiments confirm that a population of proliferating Escherichia coli in a microchannel organizes into lanes of genetically identical cells within a few generations," the authors write. "Our findings elucidate the effect of lane formation on population evolution, with potential applications ranging from microbial ecology in soil to dynamics of epithelial tissues in higher organisms."

Investigators at Washington University and other centers in the US and France consider the evolutionary consequences of geographic barriers in the Anolis lizard model. Using computational methods, the team modeled phylogenetic features in neotropical Anolis lizard species, incorporating insights on the size, distance, insularity, and geographic barriers found at nine biogeographic areas inhabited by the lizards. The authors saw signs that water acts as a strong barrier to dispersal, for example, affecting the evolution and relationships between Anolis lizards. "We designed a phylogenetic model of dispersal, extinction, and speciation that allows regional features to influence rates of biogeographic changes and applied it to the neotropical radiation of Anolis lizards," they explain, noting that their resulting model "will help biologists detect relationships between evolutionary processes and the spatial contexts in which they operate."

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