Evolutionary approaches to autism- an overview and integration

Abstract

Autism is a highly heritable neurodevelopmental disorder, which great- ly reduces reproductive success. The combination of high heritability and low re- productive success raises an evolutionary question: why was autism not eliminated  by natural selection? we review different perspectives on the evolution of autism  and propose an integration which emphasizes epistatic interactions between the ef- fects of genes during development. It is well-established that autism is a polygenic  disorder, and that the genes contributing to autism interact. If a disorder is poly- genic, it is likely that the genes underlying the disorder are also involved in traits  that are benefcial for the individual. For example, it is possible that genes involved in the development of autism are also involved in the development of intelligence. As intelligence is positively correlated with reproductive success, genes involved  in autism can possibly spread in the population. we propose that in most individu- als, the interactions between genes result in normal or high intelligence and the  absence of autism. However, in some unlucky situations, often in combination with spontaneous negative mutations, the interactions between genes can lead to the  development of autism (or other pathologies). Thus, the combination of high herita- bility and low reproductive success in autism can be explained from an evolution- ary developmental perspective that emphasizes the role of epistatic interactions in  polygenic disorders.