Effective sizes for subdivided populations.
Effective sizes for subdivided populations.
复制标题
细分群体的有效规模。
作者：
Ronald K. Chesser;O. Rhodes;Derrick W. Sugg;Andrew Schnabel
在文献中已经提出了许多有效种群大小的推导，然而，很少考虑育种结构，没有一个可以很容易地扩展到细分种群。育种结构通过其对每种性别的育种个体的数量、每种雌性的平均后代数量以及雄性和雌性产生的后代数量的方差的影响来影响基因相关性。此外，种群的等级结构由繁殖群体的数量和这些群体中雄性和雌性的迁移率决定。本研究推导出有效尺寸的分析解决方案，可应用于细分人群。参数封装育种结构和细分被用来获得传统的近交和方差有效大小。此外，它表明，有效大小可以确定任何层次的人口结构，基因相关性可以累积。推导出育种群体内基因相关性积累的有效大小（同祖有效大小）和育种群体之间的有效大小（群间有效大小）。当应用类似的假设时，结果收敛于传统的单种群测量。特别是，近亲繁殖和群间有效大小被证明是特殊情况下的共同祖先的有效大小，和群间和方差有效大小将是相等的，如果人口普查保持不变。在基因相关性开始产生后的任何时候，有效大小的瞬时解都是用传统的F统计量或过渡方程给出的。所有的有效大小收敛于一个共同的渐近值时，繁殖策略和迁移率是恒定的。渐近有效大小可以表示在固定指数和繁殖组的数量;然而，渐近的速度取决于扩散率。为了准确评估有效大小，初始，瞬时或渐近，表达式必须应用在最低水平，在该水平下，繁殖组之间的迁移是非随机的。因此，表达式可能适用于血统内的社会结构的人口，分散的人口（如果随机交换的基因普遍存在于每个人口），或组合的内部和种群间的基因流的不连续性。不认识群体的内部结构可能会导致相当大的高估近交有效大小，而通常低估方差有效大小。
Many derivations of effective population sizes have been suggested in the literature; however, few account for the breeding structure and none can readily be expanded to subdivided populations. Breeding structures influence gene correlations through their effects on the number of breeding individuals of each sex, the mean number of progeny per female, and the variance in the number of progeny produced by males and females. Additionally, hierarchical structuring in a population is determined by the number of breeding groups and the migration rates of males and females among such groups. This study derives analytical solutions for effective sizes that can be applied to subdivided populations. Parameters that encapsulate breeding structure and subdivision are utilized to derive the traditional inbreeding and variance effective sizes. Also, it is shown that effective sizes can be determined for any hierarchical level of population structure for which gene correlations can accrue. Derivations of effective sizes for the accumulation of gene correlations within breeding groups (coancestral effective size) and among breeding groups (intergroup effective size) are given. The results converge to traditional, single population measures when similar assumptions are applied. In particular, inbreeding and intergroup effective sizes are shown to be special cases of the coancestral effective size, and intergroup and variance effective sizes will be equal if the population census remains constant. Instantaneous solutions for effective sizes, at any time after gene correlation begins to accrue, are given in terms of traditional F statistics or transition equations. All effective sizes are shown to converge upon a common asymptotic value when breeding tactics and migration rates are constant. The asymptotic effective size can be expressed in terms of the fixation indices and the number of breeding groups; however, the rate of approach to the asymptote is dependent upon dispersal rates. For accurate assessment of effective sizes, initial, instantaneous or asymptotic, the expressions must be applied at the lowest levels at which migration among breeding groups is nonrandom. Thus, the expressions may be applicable to lineages within socially structured populations, fragmented populations (if random exchange of genes prevails within each population), or combinations of intra- and interpopulation discontinuities of gene flow. Failure to recognize internal structures of populations may lead to considerable overestimates of inbreeding effective size, while usually underestimating variance effective size.