Strickberger M W
Genetics. 1972 Dec;72(4):679-89. doi: 10.1093/genetics/72.4.679.
Arrowhead (AR) third chromosome arrangements of Drosophila pseudoobscura, whose competitive fitnesses had been determined in population cages, were tested for their genetic loads in homozygous, heterozygous (homokaryotypic), and heterokaryotypic (AR/CH) combinations. The results showed that their competitive population cage performances were correlated to their viabilities as homozygotes but were not correlated to their viabilities as heterozygotes or as heterokaryotypes. However, the results do not fit in too simply with the mutational model of population structure, since the improvement of homozygous viability with increased competitive fitness was not accompanied by a significant degree of dominance as measured by the regression of viabilities of heterozygotes on homozygotes. Only the AR chromosomes derived from the population with poorest competitive fitness showed marked partial dominance (h=.35). The viabilities of heterokaryotypes were markedly uniform for all chromosomes tested and produced significantly greater numbers of flies per culture than the homokaryotypes. In general, the results show that the ranking of relative competitive fitnesses of these chromosomes is not a simple extrapolation of their viabilities, although marked changes in the populations tested have occurred. It is proposed that the differences in competitive fitness, homozygous viability, and degree of dominance observed among these chromosomes, arise from differences in genetic variability which enable different linkage relationships to be established for genes affecting these attributes.
在种群笼中已测定过竞争适合度的果蝇拟暗果蝇的箭头（AR）第三染色体排列，在纯合、杂合（同核型）和异核型（AR/CH）组合中对其遗传负荷进行了测试。结果表明，它们在竞争种群笼中的表现与作为纯合子的活力相关，但与作为杂合子或异核型的活力不相关。然而，这些结果并不能简单地与种群结构的突变模型相契合，因为随着竞争适合度的增加，纯合子活力的提高并没有伴随着杂合子活力对纯合子活力回归所衡量的显著显性程度。只有来自竞争适合度最差种群的AR染色体表现出明显的部分显性（h = 0.35）。对于所有测试的染色体，异核型的活力明显一致，并且每个培养物产生的果蝇数量显著多于同核型。总体而言，结果表明这些染色体相对竞争适合度的排名并非其活力的简单外推，尽管所测试的种群已发生了显著变化。有人提出，在这些染色体中观察到的竞争适合度、纯合子活力和显性程度的差异，源于遗传变异性的差异，这使得影响这些属性的基因能够建立不同的连锁关系。
