In a paper published online in advance in Nature this week, a large international team led by investigators at the University of Minnesota presents a draft sequence of Medicago truncatula "euchromatin based on a recently completed BAC assembly supplemented with Illumina shotgun sequence, together capturing [about] 94 percent of all M. truncatula genes." The team says a whole-genome duplication that occurred approximately 58 million years ago played "a major role in shaping the M. truncatula genome and thereby contributed to the evolution of endosymbiotic nitrogen fixation." Our sister publication GenomeWeb Daily News has more on this study.
In another Nature advance online publication, MIT's Howard Chang, Jennifer Paek, and Dennis Kim report their molecular characterization of coding polymorphisms in Caenorhabditis elegans HECW-1, which encodes a conserved HECT domain-containing E3 ubiquitin ligase. "We show that two distinct polymorphisms in neighboring residues of HECW-1 each affect C. elegans behavioral avoidance of a lawn of Pseudomonas aeruginosa," Chang, Paek, and Kim write, adding that their "data establish a molecular basis for natural variation in a C. elegans behavior that may undergo adaptive changes in response to microbial pathogens."
Over in Nature Genetics, researchers at the Centre for Genomic Regulation in Barcelona report their use of "conservation-based methods to predict the impact of protein-coding variation within genes on protein function" in 19 Saccharomyces cerevisiae strains. The team also presents evaluations of those predictions "by comparing them with the observed growth rate and efficiency of 15 strains tested across 20 conditions in quantitative experiments." Overall, the CRG groups says its S. cerevisiae "predictions were more accurate when the genes reported to influence a trait were highly connected in a functional gene network."
Researchers at Harvard Medical School and elsewhere describe in Nature Genetics this week their identification of "bacterial genes under adaptive evolution by tracking recurrent patterns of mutations in the same pathogenic strain during the infection of multiple individuals." GenomeWeb Daily News has more on this study.