In this week's Nature, two independent research teams reported the discovery of a gene responsible for the colors and color patterns on the wings of butterflies and moths. The gene and a related mutation were responsible for the darkening of the peppered moth, a well-known change that took place during the industrial revolution in response to pollution and bird predation, and for the natural color pattern variation in butterflies of the genus Heliconius. In the first study, University of Liverpool researchers show that the insertion of a large portion of DNA sequence into a gene called cortex led to the dark form of the peppered moth and traced this mutation's origin to around 1819. In the other study, an international team of researchers uses population genomics and gene expression analyses to reveal that the expression of cortex varies with color patterning in Heliconius butterflies.
And in Nature Communications this week, a team of Swedish researchers presents a study analyzing the genomes of 50 killer whales, revealing details about the evolution of the animal's behavior and social structure. Killer whales exist in a wide range of habitats, and in several locations they have evolved into specialized exotypes based on diet and hunting strategies geared to their particular ecological niche. By sequencing the genomes of individual killer whales from five different ecotypes from the North Pacific and Antarctic, the researchers determined that these ecotypes have radiated globally in less than 200,000 years. They also uncovered a population decline after divergence, followed by an expansion, in all ecotypes studied. GenomeWeb has more on this study, here.