Vitalis R, Couvet D
Laboratoire de Génétique et Environnement, C.C. 065, Institut des Sciences de l'Evolution de Montpellier, Université de Montpellier II Place Eugène Bataillon, 34095 Montpellier, France.
Genet Res. 2001 Feb;77(1):67-81. doi: 10.1017/s0016672300004833.
Measures of association of genes at different loci (linkage disequilibrium) are widely used to determine whether the structure of natural populations is clonal or not, to map genes from population data, or to test for the homogeneity of response of molecular markers to background selection, for example. However, the usual definitions of parameters for gametic associations may not be suitable for all these purposes. In this paper, we derive the recursion equations for one- and two-locus identity probabilities in an infinite island model. We study the role of drift, gene flow, partial selfing and mutation model on the expected association of genes across loci. We define the 'within-subpopulation identity disequilibrium' as the difference between the joint two-locus probability of identity in state and the expected product of one-locus identity probabilities. We evaluate this parameter as a function of recombination rate, effective size, gene flow and selfing rate. Within-subpopulation identity disequilibrium attains maximum values for intermediate immigration rates, whatever the selfing rate. Moreover, identity disequilibrium may be very small, even for high selfing rates. We discuss the implications of these findings for the analysis of data from natural populations.
不同位点基因的关联度量（连锁不平衡）被广泛用于确定自然种群的结构是否为克隆性、从种群数据中定位基因，或者例如检验分子标记对背景选择的反应同质性。然而，配子关联参数的常用定义可能并不适用于所有这些目的。在本文中，我们推导了无限岛屿模型中一位点和两位点同一性概率的递归方程。我们研究了漂变、基因流、部分自交和突变模型对跨位点基因预期关联的作用。我们将“亚种群内同一性不平衡”定义为状态同一性的联合两位点概率与一位点同一性概率预期乘积之间的差异。我们将此参数评估为重组率、有效大小、基因流和自交率的函数。无论自交率如何，亚种群内同一性不平衡在中等迁移率时达到最大值。此外，即使自交率很高，同一性不平衡也可能非常小。我们讨论了这些发现对自然种群数据分析的意义。
