Sex-biased reduction in reproductive success drives selective constraint on human genes
originally posted on: 28 May 2020 (2020), unpublished
Genome-wide sequencing of human populations has revealed substantial variation among genes in the intensity of purifying selection acting on damaging genetic variants. While genes under the strongest selective constraint are highly enriched for Mendelian disorders, most of these genes are not associated with disease and therefore the nature of the selection acting on them is not known. Here we show that genetic variants that damage these genes reduce reproductive success substantially in males but much less so in females. We present evidence that this reduction is mediated by cognitive and behavioural traits, which renders male carriers of such variants less likely to find mating partners. Our findings represent strong genetic evidence that Darwin’s theory of sexual selection is shaping the gene pool of contemporary human populations. Furthermore, our results suggest that sexual selection can account for about a quarter of all purifying selection acting on human genes.
Keywords: fertility, genes, population genetics