杂种优势的进化意义探析——以适合度对随机交配群体遗传多样性的贡献为依据

Analysis of the Evolutionary Significance of Heterosis

从群体遗传的角度将杂种优势与近交衰退的定义进行类比,认为杂种优势应该用适合度来综合衡量。建立数学模型,推导出随机交配群体3种基因型RR、Rr、rr在不同适合度下的平衡状态,揭示杂种优势是群体中复等位基因存在的先决条件。发现杂种优势通过提高杂合个体的适合度,避免淘汰不同类型的基因,从而保护群体的遗传多样性,使群体具有较强的自我调节和进化潜力;让个体意义上的适应与群体层次的适应协调一致,深化了达尔文的个体选择思想。

Upon the analogy of definition of heterosis and inbreeding depresstion in terms of population genetics, the heterosis was thought to be evaluated overall with fitness. By building a mathematical model, the equilibrium status of three genotypes of random mating population （ i. e. RR, Rr and rr） under different fitness, which exposes that heterosis is the precondition for multiallele to exist in the population. The heterosis prpotects the genetic diversity and makes the population own a stronger self-control and evolution potential by improving the heterozygote＇ s fitness so as not to wash out different types of genes. It deepens Darwin＇ s thoughts of individual section by making the individual fitness consonant with population fitness.