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.Â

种群间生殖隔离的建立，可推动新物种的演化进程。该过程的遗传学理论框架指出，基因间的‘不相容’互作可发生演化，最终导致杂交个体的存活或繁殖能力下降。然而，目前学界对介导杂交不相容性的单个基因的鉴定工作进展缓慢。本研究通过多种方法联用，定位了驱动剑尾鱼（swordtail fish）杂交个体中引发黑色素瘤的不相容性相关基因。其中一个参与该不相容互作的基因，在亲缘关系较远的物种间的杂交后代中同样会引发黑色素瘤。此外，这类黑色素瘤会降低野生环境下的个体存活率，其原因大概率是鳍组织的进行性退化。本研究成功鉴定出了脊椎动物杂交不相容性的相关基因，并揭示了这些基因在自然杂交种群中的作用机制。