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Mitochondrial DNA reproduces asexually and is therefore susceptible to the accumulation of deleterious mutations. Recent results suggest that there is purifying selection against such mutations within the female germ line, which has important consequences for studies of evolution and human disease.
It is now feasible to dissect the influence of the environment on gene function in many species — a desirable goal from a biomedical, agricultural and evolutionary perspective. This article describes the progress made so far, and the analytical challenges to be overcome.
Some DNA viruses express abundant non-coding RNAs, but their function has been mostly unknown. Several recent reports show how viruses can use non-coding RNAs to tackle host defences and control their gene expression levels.
Studies of Crohn disease have benefited spectacularly from genome-wide association scans. Newly identified susceptibility loci support previously suspected underlying pathways, but also reveal hitherto unexpected putative mechanisms of this disease.