Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC, Canada.
Regroupement Québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines, (PROTEO), Université Laval, Québec, QC, Canada.
Nat Commun. 2021 May 25;12(1):3126. doi: 10.1038/s41467-021-23231-8.
Hybridization and polyploidization are powerful mechanisms of speciation. Hybrid speciation often coincides with whole-genome duplication (WGD) in eukaryotes. This suggests that WGD may allow hybrids to thrive by increasing fitness, restoring fertility and/or increasing access to adaptive mutations. Alternatively, it has been suggested that hybridization itself may trigger WGD. Testing these models requires quantifying the rate of WGD in hybrids without the confounding effect of natural selection. Here we show, by measuring the spontaneous rate of WGD of more than 1300 yeast crosses evolved under relaxed selection, that some genotypes or combinations of genotypes are more prone to WGD, including some hybrids between closely related species. We also find that higher WGD rate correlates with higher genomic instability and that WGD increases fertility and genetic variability. These results provide evidence that hybridization itself can promote WGD, which in turn facilitates the evolution of hybrids.
杂交和多倍体化是物种形成的强大机制。在真核生物中，杂交种形成通常与全基因组加倍 (WGD) 同时发生。这表明 WGD 可以通过提高适应性、恢复育性和/或增加适应性突变的获得来促进杂种的生存。或者，有人认为杂交本身可能会引发 WGD。要验证这些模型，需要在没有自然选择混杂效应的情况下，定量测定杂种中的 WGD 率。在这里，我们通过测量在放松选择下进化的 1300 多个酵母杂交的自发 WGD 率，表明某些基因型或基因型组合更容易发生 WGD，包括一些亲缘关系密切的物种之间的杂种。我们还发现，较高的 WGD 率与较高的基因组不稳定性相关，并且 WGD 提高了育性和遗传变异性。这些结果为杂交本身可以促进 WGD 的观点提供了证据，而 WGD 又促进了杂种的进化。
