“Epistasis-induced evolutionary plateaus in selection responses”

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Arnaud Le Rouzic and José M. Álvarez-Castro

Researchers provide population genetics mathematical tools to predict and understand evolutionary plateaus due to epistasis

Understanding how genes affect adaptation through either natural or artificial selection is a long-standing challenge for evolutionary biologists. Whilst it is assumed that response to selection often involves the combined action of many genes, the incidence and impact of interactions between them (epistasis) is a current matter of heated debate.

Arnaud Le Rouzic, from the CNRS at Gif-sur-Yvette, France, and José Álvarez-Castro, from the University of Santiago de Compostela, Spain, are evolutionary and quantitative geneticists who have been collaborating for about ten years on issues related to the measurement and the consequences of epistasis. Their theoretical paper appearing in The American Naturalist tips the scale towards the interpretation that these gene interactions are crucial for the understanding of evolutionary change.

That communication focuses on irregular patterns of selection response, particularly in temporary slowdowns in selection response (a phenomenon called ‘evolutionary plateau’) before accelerating again (‘release of cryptic genetic variation’). It is shown both that such plateaus will occur under a wide range of patterns of epistasis and that innovative data analyses support that they may indeed have already happened in historical selection experiments. Genetic interactions may thus affect both the outcome and the speed of evolution, and being able to account for them will help us anticipate the genetic progress in crop or animal breeding programs, or predict the adaptation of species to rapid, anthropic-driven environmental changes. Read the Article