关于回交世代方差中加性×显性分量的讨论

A Discussion on the Component of Additive×Dominance in the Genetic Variances of Backcross Generations

当两纯系存在七对基因差异,P_1中增效基因为k-k′对,减效基因 k′对时,两纯系杂交回交群体遗传方差中加性×显性分量的数学式为F=sum form i=1 to k-k′d_1h_1-sum form i=1 to k′ d_1h_1·F 的大小决定予显性齐性和基因分散的程度.因此在一般情况下,F 的遗传含义是混杂不清的.只有基因完全相联时 F=sum form i=1 to k d_1h_1,与 Mather 和Jinks 的推导结果一致,这时 F 反映显性齐性程度.

Assuming k pairs of different genes between two pure parental lines(P_1 and P_2),k-k' pairs of increasing genes and k' pairs of decreasing genes in P_1,the component of additive×dominance in the geneticvariance of the backcross generation is represented as F=sum from i=1 to k-k'd_ih_i-sum from j=1 to k'd_jh_j.The component F is determined by both the consistency of dominance and the dispersion of genes.In general,the genetic implication of the component F is complexity.Only under the situation of complete association of genes F=sum from i=1 to kd_ih_i,which agrees with the result by Mather and Jinks.In such case,F illustrates the consistency of dominance.