Nunney Leonard
Department of Biology, University of California, Riverside, California, 92521.
Evolution. 1993 Oct;47(5):1329-1341. doi: 10.1111/j.1558-5646.1993.tb02158.x.
The effective population size (N ) depends strongly on mating system and generation time. These two factors interact such that, under many circumstances, N is close to N/2, where N is the number of adults. This is shown to be the case for both simple and highly polygynous mating systems. The random union of gametes (RUG) and monogamy are two simple systems previously used in estimating N , and here a third, lottery polygyny, is added. Lottery polygyny, in which all males compete equally for females, results in a lower N than either RUG or monogamy! Given nonoverlapping generations the reduction is 33% for autosomal loci and 25% for sex-linked loci. The highly polygynous mating systems, harem polygyny and dominance polygyny, can give very low values of N /N when the generation time (T) is short. However, as T is lengthened, N approaches N/2. The influence of a biased sex ratio depends on the mating system and, in general, is not symmetrical. Biases can occur because of sex differences in either survival or recruitment of adults, and the potential for a sex-ratio bias to change N is much reduced given a survival bias. The number of juveniles present also has some influence: as the maturation time is lengthened, N increases.
有效种群大小（Ne）在很大程度上取决于交配系统和世代时间。这两个因素相互作用，在许多情况下，Ne接近于N/2，其中N是成年个体的数量。无论是简单的还是高度多配偶的交配系统，情况都是如此。配子随机结合（RUG）和一夫一妻制是先前用于估计Ne的两种简单系统，这里增加了第三种，即抽签多配偶制。在抽签多配偶制中，所有雄性平等地争夺雌性，导致Ne比RUG或一夫一妻制都要低！在世代不重叠的情况下，常染色体基因座的减少率为33%，性连锁基因座的减少率为25%。当世代时间（T）较短时，高度多配偶的交配系统，即妻妾多配偶制和优势多配偶制，会使Ne/N的值非常低。然而，随着T的延长，Ne接近N/2。性别比例偏差的影响取决于交配系统，一般来说是不对称的。偏差可能由于成年个体在生存或补充方面的性别差异而产生，并且在存在生存偏差的情况下，性别比例偏差改变Ne的可能性会大大降低。现存幼体的数量也有一定影响：随着成熟时间的延长，Ne会增加。
