In an article published this week in Science Express, a retrotransposon was linked to stubby dog legs. Retrotransposons are transposons that are first transcribed into RNA, then reverse transcribed back to DNA before being re-inserted into the genome. Looking at more than 40,000 DNA markers to find genes associated with leg length in domestic dogs, NHGRI scientists found fibroblast growth factor 4 to be strongly associated with short legs in dogs, including the dachshund, corgi, and basset hound. A story in our sister publication, Genome Web Daily News, has the full report. "Our findings suggest that retrogenes may play a larger role in evolution than has been previously thought, especially as a source of diversity within species," says lead author Heidi Parker.
A new method for sequencing ancient DNA has resulted in five complete and one almost complete Neandertal mitochondrial DNA genomes, according to work published in this week's magazine out of Svante Pääbo's lab and led by first author Adrian Briggs. The method, which reduces sample destruction and shotgun sequencing costs, revealed that Neandertal populations had a much smaller population size than modern humans or great apes. A news story reports in detail.
University of Rochester scientists found that using an antisense morpholino oligo complementary to the expanded repeats that cause myotonic dystrophy could bind the mRNA and displace the protein that this mRNA binds to in the disease state, the RNA splicing factor, Muscleblind-like 1. In an in vivo mouse model for the disease, local injection of the morpholino corrected the abnormal alternative mRNA splicing of several genes, including the muscle-specific chloride channel, CIC1. "We neutralized a toxic RNA so it released the protein stuck on it," senior author Charles Thornton said in an article at Forbes.com. A perspective goes into more detail.
Finally, Austrian scientists performed a genome-wide in vivo Drosophila RNAi screen for genes that play a role in susceptibility to intestinal infection by the bacterium Serratia marcescens, identifying several hundred genes involved in intestinal antibacterial immunity. "Among the pathways identified, we showed that the JAK-STAT signaling pathway controls host defense in the gut by regulating stem cell proliferation and thus epithelial cell homeostasis," they say in the abstract.