Caballero A, Hill W G
Institute of Cell, Animal and Population Biology, University of Edinburgh, Scotland.
Genetics. 1992 Jun;131(2):493-507. doi: 10.1093/genetics/131.2.493.
Diffusion methods were used to investigate the fixation probability, average time until fixation and extinction, and cumulative heterozygosity and genetic variance for single mutant genes in finite populations with partial inbreeding. The critical parameters in the approximation are the coefficient of inbreeding due to nonrandom mating (F) and the effective population size (Ne), which also depends on F and the variance of family size. For large Ns, the fixation probability (u) is u = 2(Ne/N)s (F + h - Fh), where N is the population census, s is the coefficient of selection of the mutant homozygote and h is the coefficient of dominance. For Poisson family size (independent Poisson distributions of selfed and nonselfed offspring with partial selfing, and independent Poisson distributions of male and female numbers with partial sib mating), Ne = N/(1 + F), and the time until fixation is approximately equal to Ne/N times the time to fixation with random mating, but this relation does not hold, however, for other distributions of family size. The cumulative nonadditive variance until fixation or loss for dominant genes is reduced with increasing F while for recessive genes it is increased with intermediate values of F. The average time until extinction of deleterious mutations is reduced by increasing F. This reduction, when expressed as a proportion, is approximately independent of the initial gene frequency as well as the selective disadvantage if this is large.
采用扩散方法研究了部分近亲繁殖有限群体中单个突变基因的固定概率、固定和灭绝前的平均时间，以及累积杂合度和遗传方差。近似中的关键参数是非随机交配导致的近亲繁殖系数（F）和有效种群大小（Ne），后者也取决于F和家庭大小的方差。对于大的N，固定概率（u）为u = 2(Ne/N)s (F + h - Fh)，其中N是种群普查数，s是突变纯合子的选择系数，h是显性系数。对于泊松家庭大小（部分自交时自交和非自交后代的独立泊松分布，以及部分同胞交配时雄性和雌性数量的独立泊松分布），Ne = N/(1 + F)，固定前的时间近似等于Ne/N乘以随机交配时的固定时间，但对于其他家庭大小分布，这种关系不成立。显性基因固定或丢失前的累积非加性方差随F增加而降低，而隐性基因则在F为中间值时增加。有害突变灭绝前的平均时间因F增加而减少。如果选择劣势较大，这种减少以比例表示时，大致与初始基因频率以及选择劣势无关。
