http://www.pnas.org/content/113/29/E4200.short

Abstract:

Hybrid sterility is a frequent outcome of crosses between closely related plant and animal species because of incompatibilities that have evolved in the parental genomes. Here, we show that a small region associated with hybrid male sterility between two closely related species of Drosophila contains two genes, both encoding DNA-binding proteins, each of which contributes to the hybrid male sterility. These results emphasize that hybrid incompatibility between well-established species is the result of numerous genetic factors, each contributing quantitatively to the incompatibility. Among these factors, DNA-binding proteins are disproportionately represented. Each incompatibility is complex, resulting from interactions between nucleotide sites in different regions of the gene, and is likely to have evolved long after the initial establishment of reproductive isolation.