Genetic hitchhiking
Genetic hitchhiking
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DOI：
10.1098/rstb.2000.0716
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发表时间：
2000-11-29
影响因子：
6.3
通讯作者：
Barton, NH
中科院分区：
文献类型：
--
作者：
Barton, NH
对一个或多个基因的选择不可避免地会干扰其他基因，即使这些基因对适应性没有直接影响。本文综述了这种遗传搭便车的理论，集中在中性位点的影响。梅纳德·史密斯和黑格介绍了经典的情况下，扰动是由于一个单一的有利突变。这与遗传变异的明显不同的影响，由于健身松散连锁基因座。波动的选择模型进行了分析，这些替代治疗的桥梁。当等位基因以λ的速率在极端频率之间扫描时，漂移速率增加了一个因子（1 + E[1/pq] λ/（2（2 λ + r），其中重组速率r远小于选择的强度。在空间结构的群体中，任何一个取代的影响都很弱，只会导致中性等位基因频率的局部增加。这种增加主要取决于相对于选择的重组率（rls），并且更弱地取决于邻域大小，Nb=4 π ρ σ（2）。空间细分可能允许局部选择性扫描比分子进化的总体速率更频繁地发生。然而，似乎不太可能这样的扫描可以足够频繁地增加中性等位基因的漂移。
Selection on one or more genes inevitably perturbs other genes, even when those genes have no direct effect on fitness. This article reviews the theory of such genetic hitchhiking, concentrating on effects on neutral loci. Maynard Smith and Haigh introduced the classical case where the perturbation is due to a single favourable mutation. This is contrasted with the apparently distinct effects of inherited variation in fitness due to loosely linked loci. A model of fluctuating selection is analysed which bridges these alternative treatments. When alleles sweep between extreme frequencies at a rate lambda, the rate of drift is increased by a factor (1 + E[1/pq]lambda/(2(2 lambda + r))), where the recombination rate r is much smaller than the strength of selection. In spatially structured populations, the effects of any one substitution are weaker, and only cause a local increase in the frequency of a neutral allele. This increase depends primarily on the rate of recombination relative to selection (rls), and more weakly, on the neighbourhood size, Nb=4 pi rho sigma (2). Spatial subdivision may allow local selective sweeps to occur more frequently than is indicated by the overall rate of molecular evolution. However, it seems unlikely that such sweeps can be sufficiently frequent to increase significantly the drift of neutral alleles.