Skip to main content
Premium Trial:

Request an Annual Quote

This Week in PNAS: Feb 21, 2017

Researchers from the University of Rhode Island track population structure and processes influencing genetic diversity in Thalassiosira rotula diatoms, looking at half a dozen microsatellite markers in T. rotula representatives collected at sites around the world. Based on genetic patterns present in diatom marine microbes collected during the same time frame at sites in the Pacific, Indian, or Atlantic Oceans, the team concludes that divergence related to the distance between populations was eclipsed by environmental and ecological selection. "[W]e provide empirical evidence for global gene flow in a marine eukaryotic microbe," the authors write, "suggesting that everything holds the potential to be everywhere, with environmental and ecological selection rather than geography or dispersal dictating the structure and evolution of diversity over space and time."

A University of Texas, Austin-led team takes a look at genome shifts in dozens of Escherichia coli populations grown over thousands of generations under one of five different temperature conditions. Using whole-genome sequencing and comparative analyses, the researchers analyzed clones taken at the end point in 30 temperature-evolved populations. In the process, they detected just over five mutations per evolved strain, on average, with an uptick in mutated gene overlap between isolates evolved under similar conditions compare to those grown at distinct temperatures.

Researchers from Russia, France, and the US describe a microfluidic droplet method for doing ultra high-throughput screening on individual cells. Their approach brought together microfluidic double emulsion technology, or double water-in-oil-in-water emulsion, with fluorescence activated cell sorting. In combination with high-throughput sequencing, and liquid chromatography-mass spectrometry, the team used its approach to analyze single-cell secretomes in yeast before applying the screening method to Saccharomyces aureus microbes and other single cell types.