Chhina Avneet K, Thompson Ken A, Schluter Dolph
Department of Zoology & Biodiversity Research Centre University of British Columbia Vancouver BC V6T 1Z4 Canada.
Evol Lett. 2022 Jan 4;6(1):34-45. doi: 10.1002/evl3.264. eCollection 2022 Feb.
Selection against mismatched traits in hybrids is the phenotypic analogue of intrinsic hybrid incompatibilities. Mismatch occurs when hybrids resemble one parent population for some phenotypic traits and the other parent population for other traits, and is caused by dominance in opposing directions or from segregation of alleles in recombinant hybrids. In this study, we used threespine stickleback fish ( L.) to test the theoretical prediction that trait mismatch in hybrids should increase with the magnitude of phenotypic divergence between parent populations. We measured morphological traits in parents and hybrids in crosses between a marine population representing the ancestral form and twelve freshwater populations that have diverged from this ancestral state to varying degrees according to their environments. We found that trait mismatch was greater in more divergent crosses for both F and F hybrids. In the F, the divergence-mismatch relationship was caused by traits having dominance in different directions, whereas it was caused by increasing segregating phenotypic variation in the F. Our results imply that extrinsic hybrid incompatibilities accumulate as phenotypic divergence proceeds.
对杂种中不匹配性状的选择是内在杂种不相容性的表型类似物。当杂种在某些表型性状上类似于一个亲本种群，而在其他性状上类似于另一个亲本种群时，就会出现不匹配，这是由相反方向的显性或重组杂种中等位基因的分离引起的。在本研究中，我们使用三刺鱼（Gasterosteus aculeatus）来检验杂种中的性状不匹配应随着亲本种群之间表型差异程度的增加而增加这一理论预测。我们测量了代表祖先形态的海洋种群与十二个根据其环境已从该祖先状态发生不同程度分化的淡水种群之间杂交的亲本和杂种的形态性状。我们发现，F1和F2杂种在差异更大的杂交组合中性状不匹配情况更严重。在F1中，差异 - 不匹配关系是由不同方向上具有显性的性状引起的，而在F2中则是由增加的分离表型变异引起的。我们的结果表明，随着表型差异的进行，外在杂种不相容性会累积。
