超显性突变的固定概率和平均固定时间
Probability of fixation and mean fixation time of an overdominant mutation.
作者信息
Nei M, Roychoudhury A K
出版信息
Genetics. 1973 Jun;74(2):371-80. doi: 10.1093/genetics/74.2.371.
The probability of fixation of an overdominant mutation in a finite population depends on the equilibrium gene frequency in an infinite population (m) and the product (A) of population size and selection intensity. If m < 0.5 (disadvantageous overdominant genes), the probability is generally much lower than that of neutral genes; but if m is close to 0.5 and A is relatively small, it becomes higher. If m > 0.5 (advantageous overdominant genes), the probability is largely determined by the fitness of heterozygotes rather than that of mutant homozygotes. Thus, overdominance enhances the probability of fixation of advantageous mutations. The average number of generations until fixation of an overdominant mutation also depends on m and A. This average time is long when m is close to 0.5 but short when m is close to 0 or 1. This dependence on m and A is similar to that of Robertson's retardation factor.
在有限种群中，超显性突变固定的概率取决于无限种群中的平衡基因频率（m）以及种群大小与选择强度的乘积（A）。如果m < 0.5（劣势超显性基因），该概率通常远低于中性基因的概率；但如果m接近0.5且A相对较小，其概率则会升高。如果m > 0.5（优势超显性基因），概率很大程度上由杂合子的适合度而非突变纯合子的适合度决定。因此，超显性提高了优势突变固定的概率。超显性突变固定前的平均世代数也取决于m和A。当m接近0.5时，这个平均时间很长，但当m接近0或1时则很短。这种对m和A的依赖类似于罗伯逊延迟因子的情况。
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