Do sex-linked male meiotic drivers contribute to intrinsic hybrid incompatibilities? Recent empirical studies from flies and rodents

Intrinsic hybrid incompatibility is one of the important isolating barriers between species. In organisms with sex chromosomes, intrinsic hybrid incompatibility often follows two rules: Haldane's rule and large-X effects. One explanation for these two rules is that sex chromosomes are hotspots for meiotic drivers that can cause intrinsic hybrid incompatibility between geographically isolated populations. Although this hypothesis seems plausible and several empirical data are consistent with it, we are still unsure whether such mechanisms occur in nature, particularly with respect to speciation with gene flow. Here, we review empirical studies that have investigated the roles of meiotic drive in sex-chromosome evolution and speciation and propose future studies necessary for testing this hypothesis.

Automated summary

This article discusses the importance of intrinsic hybrid incompatibility as a barrier between species, especially in organisms with sex chromosomes. It explains two rules, Haldane's rule and large-X effects, that contribute to intrinsic hybrid incompatibility. The hypothesis suggests that sex chromosomes serve as hotspots for meiotic drivers that cause this incompatibility. Although empirical data supports this hypothesis, further research is needed to understand the occurrence of these mechanisms in nature, particularly in relation to speciation with gene flow.