EPISTASIS AND THE EFFECT OF FOUNDER EVENTS ON THE ADDITIVE GENETIC VARIANCE
EPISTASIS AND THE EFFECT OF FOUNDER EVENTS ON THE ADDITIVE GENETIC VARIANCE
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DOI：
10.2307/2409030
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发表时间：
1988-05-01
期刊：
影响因子：
3.3
通讯作者：
GOODNIGHT, CJ
中科院分区：
文献类型：
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作者：
GOODNIGHT, CJ
创始人事件的模型关注的是创始人事件后基因变异的减少。然而，最近的研究（Bryant et al., 1986; Good night, 1987）表明，当种群中存在上位性遗传变异时，在一个创始者事件发生后，群内的总遗传变异实际上可能会增加。由于加性遗传变异是种群的统计特性，可以随着近交水平的变化而变化，一些上位遗传变异可能在建立事件中转化为加性遗传变异。这里提出的模型表明，一些加性加性上位遗传变异在奠基人事件后转化为加性遗传变异。此外，上位性转化为加性遗传变异的数量是重组率和繁殖体大小的函数。对于两个个体的单个创始事件，在创始事件之后，祖先群体中高达75%的上位性方差可能成为加性遗传方差。对于涉及两个个体自由重组的建立事件，建立事件后上位性对加性遗传方差的相对贡献等于其在建立事件前总遗传方差的比例。与适应度密切相关的性状预计具有相对较小的加性遗传变异，但可能具有大量的非加性遗传变异。奠基人事件在适合度性状的进化中可能很重要，不是因为它们导致遗传变异的减少，而是因为它们导致加性遗传变异的增加。
Models of founder events have focused on the reduction in the genetic variation following a founder event. However, recent work (Bryant et al., 1986; Good night, 1987) suggests that when there is epistatic genetic variance in a population, the total genetic variance within demes may actually increase following a founder event. Since the additive genetic variance is a statistical property of a population and can change with the level of inbreeding, some of the epistatic genetic variance may be converted to additive genetic variance during a founder event. The model presented here demonstrates that some of the additive-by-additive epistatic genetic variance is converted to additive genetic variance following a founder event. Furthermore, the amount of epistasis converted to additive genetic variance is a function of the recombination rate and the propagule size. For a single founder event of two individuals, as much as 75% of the epistatic variance in the ancestral population may become additive genetic variance following the founder event. For founder events involving two individuals with free recombination, the relative contribution of epistasis to the additive genetic variance following a founder event is equal to its proportion of the total genetic variance prior to the founder event. Traits closely related to fitness are expected to have relatively little additive genetic variance but may have substantial nonadditive genetic variance. Founder events may be important in the evolution of fitness traits, not because they lead to a reduction in the genetic variance, but rather beause they lead to an increase in the additive genetic variance.