Hedrick P W
Genetics. 1976 Jul;83(3 PT.2):551-71.
The change in gene frequency for two X-linked mutants, gamma and omega, in a number of experiments was compared to that predicted from a genetic simulation program which utilized estimated differences in relative mating ability, fecundity, and viability. The simulation gave excellent predictions of gene frequency change even when experiments were started with different initial gene frequencies in the males and females or when the two loci were segregating simultaneously. The rate of elimination was slower when there were unequal initial gene frequencies than when males and females had equal initial gene frequencies. Simulation demonstrated that this was a general phenomenon when there is strong selection but that the opposite is true for weak selection. In two other experiments, the mating advantage of wild-type males was balanced by a fecundity advantage in mutant females. In all four replicates of both experiments, the mutant was maintained for several generations at the high initial frequency but then decreased quickly and was eliminated. Results obtained restarting one of these experiments with flies from a generation after the decline in gene frequency indicated that a linked gene and not frequency-dependent selection was responsible for the unpredictable gene-frequency change in the mutant. Using a least squares technique, it was found that a recessive fecundity locus 15 map units from the omega locus gave the best fit for both experiments.
在一系列实验中，比较了两个X连锁突变体gamma和omega的基因频率变化与利用相对交配能力、繁殖力和生存力估计差异的遗传模拟程序预测的变化。即使实验开始时雄性和雌性的初始基因频率不同，或者两个基因座同时分离，模拟也能很好地预测基因频率变化。当初始基因频率不相等时，消除速率比雄性和雌性初始基因频率相等时慢。模拟表明，当存在强选择时，这是一种普遍现象，但对于弱选择则相反。在另外两个实验中，野生型雄性的交配优势被突变型雌性的繁殖力优势所平衡。在这两个实验的所有四个重复中，突变体在高初始频率下维持了几代，但随后迅速下降并被消除。在基因频率下降一代后用果蝇重新启动其中一个实验得到的结果表明，一个连锁基因而非频率依赖选择导致了突变体中不可预测的基因频率变化。使用最小二乘法技术发现，一个距omega基因座15个图距单位的隐性繁殖力基因座最适合这两个实验。
