In the early, online edition of Genome Research, the National Human Genome Research Institute's Elaine Ostrander and colleagues from the US and Ireland describe variants falling in and around half a dozen genes that seem to explain a good deal of the diminished size seen in some dog breeds. The group did fine mapping on four loci linked to canine body size in past work. After finding five markers at these sites in the genome, investigators went on to genotype these variants in hundreds of domestic dogs and dozens of their wild relatives. Results from those and other assessments suggest six genes account for as much as half of the size variation found in dog breeds that typically weigh 90 pounds or less.
Using whole-genome sequence data for 31 butterflies, researchers from the UK, the US, and Colombia found evidence that butterflies within the Heliconius genus have experienced speciation even in the midst of admixture and gene flow between species. The study authors report signs of ongoing admixture stretching back to the time of early Heliconius speciation, though sequences around genes related to divergent physical features tended to show relatively low admixture signals. "Overall," they say, "these results show that species divergence can occur in the face of persistent and genome-wide admixture over long periods of time."
An Institute of Cancer Research-led team presents a mutation profiling method for assessing individual cancer cells. In their Genome Research study, the researchers demonstrated the feasibility of their single cell mutation profiling method — which hinges on multiplex, targeted, high-throughput quantitative PCR and Fluidigm's BioMark HD microfluidic device — using leukemia cells with known mutation patterns. Findings from the proof-of-principle analysis indicate that the method can pick up a range of mutation types, including gene fusions, copy number shifts, and single base changes.