Goodisman M A, Crozier R H
Department of Genetics, La Trobe University, Bundoora, Australia.
Hereditas. 2001;134(2):161-9. doi: 10.1111/j.1601-5223.2001.00161.x.
Hybrid zone models often consider environment-independent selection to operate against all hybrids. However, empirical studies suggest that hybrids may be as fit or fitter than the hybridizing parental taxa in some environments. In this study we develop a novel mathematical model to explore the effects of one form of hybrid superiority on the genetic structure of hybrid zones. Our primary goals were to investigate the allele frequency clines at a locus experiencing overdominant selection and at a linked neutral or underdominant locus. Our results indicate that overdominant selection results in flat equilibrium allele frequency clines throughout the hybrid zone and an excess of heterozygosity relative to Hardy-Weinberg equilibrium. However, the genetic clines at linked neutral or underdominant loci tend not to reflect this overdominance even when the loci are tightly linked. Overall, we conclude that overdominance is unlikely to be detected in genetic surveys unless many loci are assayed.
杂交带模型通常认为与环境无关的选择作用于所有杂种。然而，实证研究表明，在某些环境中杂种可能与杂交亲本类群一样适应或更适应。在本研究中，我们开发了一种新颖的数学模型，以探讨一种杂种优势形式对杂交带遗传结构的影响。我们的主要目标是研究在经历超显性选择的位点以及连锁的中性或亚显性位点处的等位基因频率渐变群。我们的结果表明，超显性选择导致整个杂交带的平衡等位基因频率渐变群平坦，并且相对于哈迪-温伯格平衡存在过量的杂合性。然而，即使这些位点紧密连锁，连锁的中性或亚显性位点处的遗传渐变群也往往不反映这种超显性。总体而言，我们得出结论，除非检测许多位点，否则在遗传调查中不太可能检测到超显性。
