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This Week in PNAS: Feb 27, 2018

In PNAS this week, a team led by investigators in Germany and Chile tackles microbial habitat patterns in Chile's Atacama Desert, a "hyper-arid" desert considered one of the driest sites on the globe. Based on soil testing, metabolic profiling, microbial genome replication rates and community patterns, and other approaches, the researchers saw signs that indigenous microbial communities crop up intermittently in the Atacama Desert, despite its inhospitable environment. "We infer that the microbial populations have undergone selection and adaptation in response to their specific soil microenvironment," the authors say, arguing that "even the hyper-arid Atacama Desert can provide a habitable environment for microorganisms that allows them to become metabolically active following an episodic increase in moisture and that once it decreases, so does the activity of the microbiota."


Also in PNAS this week, Columbia University researchers attempt to predict flu transmission over time and space, taking human mobility patterns into account. By bringing commuter data together with clinical and laboratory information for influenza type A-infected individuals, the team came up with an "operational forecast system" for predicting influenza's spatiotemporal spread in the US. When they retrospectively applied the metapopulation model to influenza data from nearly three-dozen American states, the authors were able to forecast local flu events as early as six weeks before the disease descended on a community. "[T]he metapopulation prediction system forecasts influenza outbreak onset, peak timing, and peak intensity more accurately than isolates location-specific forecasts," they write, noting that the "proposed framework could be applied to emergent respiratory viruses and, with appropriate modifications, other infectious diseases."


Finally, an international team presents findings from a genomic analysis of existing and extinct elephantid species, uncovering signs of recurrent hybridization events between distinct elephantids as well as pronounced instances of isolation. Along with a new, high-quality reference genome for the African savanna elephant, the researchers generated genomes for more than a dozen ancient and modern species — from forest, savanna, and Asian elephants to mammoths and mastodons. "While hybridization events have shaped elephantid history in profound ways," they note, "isolation also appears to have played an important role."

The Daily Scan's sister publication, GenomeWeb Daily News, has more on the study, here.