Next January 27 at 12 am it will take place the seminar "African killifishes shed light on the evolutionary and mechanistic basis of aging"  by Dario R.Valenzano from Evolutionary and Experimental Biology of Ageing, Max Planck Institute for Biology of Ageing. Cologne. Germany.

Abstract

"Whether adaptive evolution or genetic drift shape life history trait evolution across species has been a long-standing question in evolutionary biology. African killifishes (oviparous Cyprinodontiformes) offer a natural experiment in life history trait evolution as they independently evolved short lifespan and rapid aging (annual life cycles) at least three times. Using a comprehensive whole-genome sampling of 46 species of African killifishes, we found that short-lived species, which evolved in dry climates, underwent nuclear and mitochondrial genome expansion. Proliferation of transposable elements drove nuclear genome expansion in annual species, which also display higher gene family turn-over rates and relaxed selection in genes in known ageing pathways. Whole-genome re-sequencing in wild Nothobranchius populations showed bottle-necks and a genome-wide signature of relaxation of selection in populations from drier climates. We found that ecology drove the evolution of short lifespan, associated with the genome-wide accumulation of tens of thousands of slightly deleterious mutations. Hence, drift, more than adaptive evolution, was the dominant signal underlying the evolution of short lifespan and rapid aging in annual killifish. Extending our analysis to humans, we found that genes evolving neutrally in our species tend are significantly associated with aging pathways and that genes differentially expressed in tissues from old individuals compared to young individuals evolved significantly more neutrally. Overall, our results indicate that species with limited population size, undergoing repeated population oscillation due to harsh climate, accumulate a large number of deleterious gene variants, preferentially in genes affecting late-life maintenance."