Nomura Tetsuro
Department of Biotechnology, Faculty of Engineering, Kyoto Sangyo University Kyoto, Japan.
Evol Appl. 2008 Aug;1(3):462-74. doi: 10.1111/j.1752-4571.2008.00015.x. Epub 2008 Mar 18.
The effective population size, N e, is an important parameter in population genetics and conservation biology. It is, however, difficult to directly estimate N e from demographic data in many wild species. Alternatively, the use of genetic data has received much attention in recent years. In the present study, I propose a new method for estimating the effective number of breeders N eb from a parameter of allele sharing (molecular coancestry) among sampled progeny. The bias and confidence interval of the new estimator are compared with those from a published method, i.e. the heterozygote-excess method, using computer simulation. Two population models are simulated; the noninbred population that consists of noninbred and nonrelated parents and the inbred population that is composed of inbred and related parents. Both methods give essentially unbiased estimates of N eb when applied to the noninbred population. In the inbred population, the proposed method gives a downward biased estimate, but the confidence interval is remarkably narrowed compared with that in the noninbred population. Estimate from the heterozygote-excess method is nearly unbiased in the inbred population, but suffers from a larger confidence interval. By combining the estimates from the two methods as a harmonic mean, the reliability is remarkably improved.
有效种群大小Ne是种群遗传学和保护生物学中的一个重要参数。然而，在许多野生物种中，很难直接从种群统计学数据中估计Ne。近年来，利用遗传数据的方法受到了广泛关注。在本研究中，我提出了一种新方法，可根据样本后代中等位基因共享（分子共祖系数）的一个参数来估计有效繁殖个体数Neb。通过计算机模拟，将新估计器的偏差和置信区间与已发表方法（即杂合子过剩法）的偏差和置信区间进行了比较。模拟了两种种群模型：由非近亲且无亲缘关系的亲本组成的非近交种群，以及由近亲且有亲缘关系的亲本组成的近交种群。当应用于非近交种群时，两种方法对Neb的估计基本无偏差。在近交种群中，所提出的方法给出的估计值存在向下偏差，但与非近交种群相比，置信区间显著变窄。杂合子过剩法在近交种群中的估计几乎无偏差，但置信区间较大。将两种方法的估计值作为调和平均数相结合，可靠性得到显著提高。
