Pudovkin A I, Zaykin D V, Hedgecock D
Institute of Marine Biology, Vladivostok, Russia.
Genetics. 1996 Sep;144(1):383-7. doi: 10.1093/genetics/144.1.383.
The important parameter of effective population size is rarely estimable directly from demographic data. Indirect estimates of effective population size may be made from genetic data such as temporal variation of allelic frequencies or linkage disequilibrium in cohorts. We suggest here that an indirect estimate of the effective number of breeders might be based on the excess of heterozygosity expected in a cohort of progeny produced by a limited number of males and females. In computer simulations, heterozygote excesses for 30 unlinked loci having various numbers of alleles and allele-frequency profiles were obtained for cohorts produced by samples of breeders drawn form an age-structured population and having known variance in reproductive success and effective number. The 95% confidence limits around the estimate contained the true effective population size in 70 of 72 trials and the Spearman rank correlation of estimated and actual values was 0.991. An estimate based on the heterozygote excess might have certain advantages over the previous estimates, requiring only single-locus and single-cohort data, but the sampling error among individuals and the effect of departures from random union of gametes still need to be explored.
有效种群大小的重要参数很少能直接从人口统计学数据中估计出来。有效种群大小的间接估计可以从遗传数据中得出，比如等位基因频率的时间变化或群体中的连锁不平衡。我们在此提出，有效繁殖者数量的间接估计可能基于有限数量的雄性和雌性所产生的后代群体中预期的杂合子过剩。在计算机模拟中，对于由从年龄结构群体中抽取的繁殖者样本产生的群体，获得了具有不同等位基因数量和等位基因频率分布的30个不连锁基因座的杂合子过剩情况，这些繁殖者样本具有已知的繁殖成功率方差和有效数量。在72次试验中的70次试验中，估计值周围的95%置信区间包含了真实的有效种群大小，估计值与实际值的斯皮尔曼等级相关性为0.991。基于杂合子过剩的估计可能比之前的估计有某些优势，只需要单基因座和单群体数据，但个体间的抽样误差以及配子随机结合偏离的影响仍有待探索。
