In Nature this week, an international team of researchers presents an analysis of the genome sequences of 198 living bird species, offering an in-depth look at the evolutionary relationships of modern birds. The researchers analyzed more than 390,000 bases of genomic sequence data from each of the species, which represent all major bird lineages plus two crocodilian subgroups. The findings are consistent with the fossil record, supporting a major radiation of birds follow the Cretaceous-Palaeogene mass extinction about 65 million years ago, and point to the presence of five major bird groups.
And in Nature Immunology, researchers from the Baylor College of Medicine present data implicating a microRNA in emphysema. The researchers found that microRNA-22 is overexpressed in the lungs of smokers, as compared with non-smokers, and that mice exposed to cigarette smoke or particles that mimic soot experience an increase in the miRNAs expression. In in vitro experiments, the group demonstrated that miR-22 inhibits the expression of a specific enzyme that mediates the recruitment of inflammatory-response cells, whose activation contributes to the loss of lung function. When mice were modified so that they cannot express miR-22, they did not develop lung disease after exposure to smoke or carbon nanoparticles, suggesting that the miRNA could be a target for treating emphysema and other inflammatory conditions.