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This Week in PLoS: Mar 16, 2009

In a paper in PLoS Genetics, scientists looked across two populations to find that "increases in mobility, urbanization, and cross-population mating over the last century have substantially reduced inbreeding, and left a distinctive trace in the genome of modern Americans," blogger Daniel MacArthur says at Genetic Future. In looking at the level of autozygosity, or extended tracts of homozygosity, across the genomes of a representative population of 809 unrelated North Americans of European descent ranging in chronological age from 19 to 99 years old, they found that runs of homozygosity steadily decrease in size and frequency as time progresses.

Computational scientists have built an algorithmic model, EMMA (Evolutionary Model-based cis-regulatory Module Analysis), of cross-species cis-regulatory module evolution that "captures different modes of evolution of functional transcription factor binding sites (TFBSs) and the background sequences," they say in the abstract at PLoS Computational Biology. Their novel approach uses a probabilistic model of gains and losses of TFBSs, and uses conserved binding sites among species to improve alignment.

In other work appearing in PLoS Genetics, researchers created a protein interaction map of human homologs of proteins that affect longevity in invertebrate species. The "longevity network" is made up of 175 human homologs of proteins known to increase longevity through loss of function in yeast, nematode, or fly, and 2,163 additional human proteins that interact with these homologs. They showed that by knocking down 18 proteins known to affect aging in human muscle in C. elegans, 33 percent of these extended life span in the worm.

Japanese scientists have created a method to analyze metabolic behavior of bacteria in real time. Using real-time metabolotyping (RT-MT), they elucidated the pathway for linolenic acid hydrogenation by a gastrointestinal bacterium, Butyrivibrio fibrisolvens, as well as identified trans11, cis13 conjugated linoleic acid as the intermediate of linolenic acid hydrogenation by B. fibrisolvens.