Causative genes of intrinsic hybrid incompatibility in animals and plants: what we have learned about speciation from the molecular perspective

Abstract

Intrinsic hybrid incompatibility is one of the important reproductive isolating mechanisms between species. Several genes causing intrinsic hybrid incompatibilities have been identified over the last few decades. Information on these causative genes and mutations of intrinsic hybrid incompatibilities helps us answer several important evolutionary questions regarding the plausibility of classic theoretical models of intrinsic hybrid incompatibilities, the evolutionary driving forces involved, and the repeatability of molecular mechanisms across taxa. Here, we made an updated list of the causative genes of intrinsic hybrid incompatibilities in animals and plants. Although several empirical cases are consistent with the classic two-locus Dobzhansky-Muller incompatibility (DMI) model, there are many cases in which epistatic interactions are more complex. Animals and plants appear to share several molecular mechanisms of intrinsic hybrid incompatibility. In both animals and plants, many causative genes evolve under genomic conflicts. Some taxonomic differences may result from inherent physiological differences. As most studies are biased toward a limited number of model organisms, further studies on natural systems across diverse taxa are necessary for the quantitative assessment of these patterns in nature.