THE EFFECT OF LINKAGE AND POPULATION-SIZE ON INBREEDING DEPRESSION DUE TO MUTATIONAL LOAD
THE EFFECT OF LINKAGE AND POPULATION-SIZE ON INBREEDING DEPRESSION DUE TO MUTATIONAL LOAD
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DOI：
10.1017/s0016672300030160
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发表时间：
1992-02-01
影响因子：
1.5
通讯作者：
CHARLESWORTH, B
中科院分区：
文献类型：
--
作者：
CHARLESWORTH, D;MORGAN, MT;CHARLESWORTH, B
利用一个多位点突变为部分隐性有害等位基因的有限群体随机模型，研究了群体大小和位点间连锁对群体平均适合度和近交衰退值的影响。虽然选定的位点之间的连锁减少了近交衰退的数量，人口规模和重组率对这些数量都没有强烈的影响，除非假设值非常小。我们还调查了如何部分连锁的基因座，决定健身影响入侵的等位基因在一个修饰基因座，控制自交率的人口。在大多数的情况下，修改器的选择方向是一致的，发现在我们以前的确定性计算。然而，有一些证据表明，修饰基因座和选定的基因座之间的连锁使异交不太可能进化;更多的等位基因的损失，促进异交发生在运行与连锁比运行与自由重组。我们还研究了引入携带有害突变的群体的中性等位基因的命运。在低频率引入的中性等位基因的损失时间短于那些预测的等位基因在没有选定的基因座，考虑到减少的有效人口规模，由于近亲繁殖。以前的研究仅限于远系繁殖的种群，以及频率接近一半的等位基因，并发现了相反方向的影响。因此，似乎中性和选择基因座之间的关联可能会产生不同的影响，根据中性等位基因的初始频率。
Using a stochastic model of a finite population in which there is mutation to partially recessive detrimental alleles at many loci, we study the effects of population size and linkage between the loci on the population mean fitness and inbreeding depression values. Although linkage between the selected loci decreases the amount of inbreeding depression, neither population size nor recombination rate have strong effects on these quantities, unless extremely small values are assumed. We also investigate how partial linkage between the loci that determine fitness affects the invasion of populations by alleles at a modifier locus that controls the selfing rate. In most of the cases studied, the direction of selection on modifiers was consistent with that found in our previous deterministic calculations. However, there was some evidence that linkage between the modifier locus and the selected loci makes outcrossing less likely to evolve; more losses of alleles promoting outcrossing occurred in runs with linkage than in runs with free recombination. We also studied the fate of neutral alleles introduced into populations carrying detrimental mutations. The times to loss of neutral alleles introduced at low frequency were shorter than those predicted for alleles in the absence of selected loci, taking into account the reduction of the effective population size due to inbreeding. Previous studies have been confined to outbreeding populations, and to alleles at frequencies close to one-half, and have found an effect in the opposite direction. It therefore appears that associations between neutral and selected loci may produce effects that differ according to the initial frequencies of the neutral alleles.