In the early, online issue of PNAS this week, Canadian and American researchers report that turkeys were domesticated at least twice in North America. Based on their analyses of ancient mitochondrial DNA from 149 turkey bones and dozens of dung samples from archaeological sites in the US combined with comparisons of modern samples and GenBank data, the team found that a now extinct domesticated turkey sub-species once existed in the American southwest. As Brandon Keim reports in Wired online, these southwest turkeys died out, while Aztec turkeys were taken to Europe, bred with local sub-species, and eventually brought back to North America.
University of Oslo researcher Martin Vingron and his team report that they came up with quantitative models for using histone modification information to predict gene expression in human CD4+ T-cells. They found that the expression of genes with different promoter types could be predicted by distinct sets of histone modifications. "[T]he connections between histone modifications and gene expression seem to be general," they write, "as we were able to predict gene expression levels of one cell type using a model trained on another one."
Pacific Biosciences chief scientific officer Eric Schadt and his team demonstrate that lineage-specific selection has altered the expression of more than a hundred Saccharomyces cerevisiae genes, including several involved in the ergosterol biosynthesis pathway. "[T]hese results suggest that adaptive evolution of gene expression is common in yeast, that regulatory adaptation can occur at the level of entire pathways, and that similar genome-side scans may be possible in other species, including humans," they write.
An international research team identified ten recessive mutations in the preproinsulin gene INS — causing everything from gene deletions to altered transcription — that curb insulin production and cause neonatal diabetes in 15 probands. The findings suggest both recessive and previously reported dominant mutations in INS can lead to neonatal diabetes.