Who runs fastest in an adaptive landscape: Sexual versus asexual reproduction

TL;DR

This paper compares the adaptation speed of sexual and asexual populations under biased selection, finding that sexual reproduction's increased variation often does not lead to faster adaptation due to mating dynamics.

Contribution

It challenges the Weismann hypothesis by showing that increased genetic variation in sexual reproduction does not always translate to faster adaptation.

Findings

Asexual populations can sometimes adapt as fast or faster than sexual ones.

Mating with lower-fitness individuals reduces the reproductive advantage of sexual reproduction.

In most model parameters, sexual reproduction's extra variation does not significantly accelerate adaptation.

Abstract

We compare the speed with which a sexual, respectively an asexual, population is able to respond to a biased selective pressure. Our model focuses on the Weismann hypothesis that the extra variation caused by crossing-over and recombination during sexual reproduction allows a sexual population to adapt faster. We find, however, that the extra variation amongst the progeny produced during sexual reproduction for most model parameters is unable to overcome the effect that parents with a high individual fitness in general must mate with individuals of lower individual fitness resulting in a moderate reproductive fitness for the pair.