By blocking the expression of different genes in Caenorhabditis elegans, researchers from the Chinese Academy of Sciences have identified two epigenetic factors that prevent healthy aging. As reported in Nature this week, the team performed a genome-wide RNA interference screen in the nematodes, focusing on genes that regulate behavioral deterioration in aging. They find that the neuronal epigenetic reader BAZ-2 and the neuronal histone 3 lysine 9 methyltransferase SET-6 accelerate behavioral deterioration in the worms by reducing mitochondrial function, repressing the expression of nuclear-encoded mitochondrial proteins. Notably, expression of the human versions of the epigenetic regulators appears linked to the progression of Alzheimer's disease, while inhibiting the murine ortholog of BAZ-2 attenuates age-dependent body weight gain and cognitive decline in mice. The findings suggest that "targeting repressive epigenetic regulators is a potential strategy for improving behavioral performance and achieving healthy aging," the study's authors write.
A large-scale genomic analysis reported in Nature Ecology & Evolution this week reveals widespread patterns of gene loss in the evolution of the animal kingdom. Researchers from the University of Essex and the University of Oxford analyze 102 metazoan genomes including over 2.6 million protein sequences, inferring major genomic patterns associated with the variety of animal forms from the superphylum to phylum level. The scientists uncover a significant amount of gene loss that occurred during the evolution of two major groups of bilaterian animals, Ecdysozoa and Deuterostomia, and further loss in several deuterostome lineages. They also find large genome novelties among deuterostomes and protostomes. "These findings paint a picture of evolution in the animal kingdom in which reductive evolution at the protein-coding level played a major role in shaping genome composition," they write.