In this week's Nature, an international team of researchers reports on the sequencing and analysis of the genomes of two acorn worms, gaining new insights into the origins of deuterostomes — a diverse group of organisms that includes the worms, starfish, and humans, and whose phylogeny is unclear. By comparing the worms' genomes to those of other animals, the researchers found more than 30 deuterostomes genes with sequences that are significantly different than those of other multicellular organisms. They also found a cluster of six deuterostome-specific genes associated with the development of pharyngeal gill slits, which are increasingly believed to a defining feature of deuterostomes. GenomeWeb has more on this study here.
And in Nature Genetics, two groups of scientists publish studies suggesting that a single chromosomal inversion containing more than 100 genes is responsible for the dramatically different phenotypes found in males from the ruff species Philomachus pugnax. The ruff has three distinctive types of males: independent males with multi-colored ornamental plumage that defend territories, non-territorial males with only white plumage, and submissive faeder males, which resemble females and only mate when independents are distracted. By sequencing the genomes of the three types of ruffs, the investigators found a region on a chromosome that was inverted in satellite and faeder males compared with independents. The region, which can be thought of a sort of "supergene," can be inherited as a single block containing move than 100 genes. One group of researchers speculates that the inversion first occurred 3.8 million years ago and accumulated mutations over time that led to the differences between satellites and faeders. The other identified genes are involved in hormone signaling and may contribute to the behavioral differences between the bird types. GenomeWeb also covers this here.