Wiehe T, Slatkin M
Department of Integrative Biology, University of California, Berkeley, California 94720-3140, USA.
Theor Popul Biol. 1998 Feb;53(1):75-84. doi: 10.1006/tpbi.1997.1342.
We analyze a multiple-locus extension of the Levene (1953) model of population subdivision. We show that stable or quasistable linkage disequilibrium between two selected loci can be maintained even with free recombination, provided that there is a strong enough epistatic interaction. We then consider the dynamics of a third neutral locus and show that its approach to linkage equilibrium depends on the recombination rates and the selection intensities. There is an embedding or hitchhiking effect that extends the time during which a neutral locus which is closely linked to one of the selected loci remains in disequilibrium with both selected loci. Therefore, strong disequilibrium between two loci does not necessarily indicate that those loci are themselves selected, but it does indicate that there is strong selection acting at least on nearby loci. This property implies a warning that screening for linkage disequilibrium as a tool to identify functionally important sites in a genome can be misleading.
我们分析了莱文（1953年）种群细分模型的多基因座扩展。我们表明，即使在自由重组的情况下，只要存在足够强的上位性相互作用，两个选定基因座之间的稳定或准稳定连锁不平衡也能够得以维持。接着，我们考虑了第三个中性基因座的动态变化，并表明它达到连锁平衡的方式取决于重组率和选择强度。存在一种嵌入或搭便车效应，这种效应延长了与其中一个选定基因座紧密连锁的中性基因座与两个选定基因座保持不平衡的时间。因此，两个基因座之间的强不平衡并不一定表明这些基因座本身受到了选择，但确实表明至少在附近的基因座上存在强烈的选择作用。这一特性意味着一个警示，即把筛查连锁不平衡作为识别基因组中功能重要位点的工具可能会产生误导。
