Nordborg M, Franklin I R, Feldman M W
Department of Biological Sciences, Stanford University, California 94305-5020, USA.
Theor Popul Biol. 1995 Jun;47(3):365-92. doi: 10.1006/tpbi.1995.1017.
Most analyses of two-locus viability models have assumed that the fitness of double heterozygotes are the same whether in the cis or trans configuration. This assumption is unlikely to hold for polymorphic sites within the same locus. We examine the quantitative and qualitative effects of incorporating cis-trans viability differences into a number of deterministic two-locus models. A new result is the finding that two asymmetric equilibria with similar levels of linkage disequilibrium, but different gene frequencies, may arise in quite realistic biological models. The general, and most important, conclusion is that high levels of linkage disequilibrium may be generated by very small selective differences in cis and trans. Polymorphic sites that interact selectively are expected to show high levels of linkage disequilibrium. Conversely, if two polymorphic sites within a gene are found to be in linkage equilibrium, it is likely that one or both are selectively neutral.
大多数对双基因座生存力模型的分析都假定，无论处于顺式还是反式构型，双杂合子的适合度都是相同的。这一假设对于同一基因座内的多态性位点而言不太可能成立。我们研究了将顺反式生存力差异纳入多个确定性双基因座模型后的定量和定性影响。一个新的结果是，在相当现实的生物学模型中可能会出现两个具有相似连锁不平衡水平但基因频率不同的不对称平衡。总体而言，也是最重要的结论是，顺式和反式中非常小的选择差异可能会产生高水平的连锁不平衡。预期具有选择性相互作用的多态性位点会表现出高水平的连锁不平衡。相反，如果发现基因内的两个多态性位点处于连锁平衡状态，则很可能其中一个或两个位点是选择性中性的。
