Natural hybridization reveals incompatible alleles that cause melanoma in swordtail fish

The establishment of reproductive barriers between populations can fuel
the evolution of new species. A genetic framework for this process posits
that "incompatible" interactions between genes can evolve that
result in reduced survival or reproduction in hybrids. However, progress
has been slow in identifying individual genes that underlie hybrid
incompatibilities. Here, we use a combination of approaches to map the
genes that drive the development of an incompatibility that
causes melanoma in swordtail fish hybrids. One of the genes
involved in this incompatibility also causes melanoma in hybrids between
distantly related species. Moreover, this melanoma reduces survival in the
wild, likely due to progressive degradation of the fin. This work
identifies genes underlying a vertebrate hybrid incompatibility and
provides a glimpse into the action of these genes in natural hybrid
populations.