In PLoS Genetics this week, researchers at the University of California, Santa Barbara, and Texas A&M University report their use of population-based re-sequencing on experimentally evolved Drosophila melanogaster populations, with which they determined the "genetic basis of body size variation" in the fruit fly. This basis, the team writes, is highly polygenic — "significantly differentiated variants are limited to single genes at some loci, allowing precise hypotheses to be formed regarding causal polymorphisms, while other significant regions are large and contain many genes."
Also in PLoS Genetics this week, researchers at institutions across Spain demonstrate that "viral genome segmentation can result from a trade-off between genetic content and particle stability." The team compared a stable segmented bipartite RNA virus with its ancestral, non-segmented counterpart under identical genomic contexts, and found evidence to suggest that "genome segmentation allows maximizing the genetic content without the detrimental effect in stability derived from increasing genome length."
Meanwhile, over in PLoS One, investigators at the Bigelow Laboratory for Ocean Sciences in Maine and Swarthmore College in Pennsylvania report their use of cultivation-independent techniques to determine whether the freshwater Leptothrix ochracea is related to other morphologically similar, sheathed microorganisms. "Using single-cell genomics, pyrosequencing, and FISH," the team found that "SSU rRNA gene of L. ochracea shares 96 percent homology with its closet cultivated relative, L. cholodnii."
In another PLoS One paper published this week, the Chinese Academy of Science's Dapeng Wang and Jun Yu show that "both size and GC-content of minimal introns are selected in human populations." In particular, Wang and Ju report that "minimal introns longer than an optimal size — 87 nt — tend to have a higher ratio of deletion to insertion than those that are shorter than the optimal size," and that "minimal introns with lower GC content tend to be more frequently deleted than those with higher GC content." Overall, the authors say, the "mutation dynamics of minimal introns in keeping their near-optimal size and GC content" may play important functional roles in gene regulation.