Powell J R
Genetics. 1979 Jun;92(2):613-22. doi: 10.1093/genetics/92.2.613.
Morph frequencies of three related polymorphisms were determined in ten natural populations of Drosophila pseudoobscura. They are the well-known inversion polymorphism of the third chromosome and the polymorphism for alpha-amylase produced by the structural gene Amy (which resides on the third chromosome). The third polymorphism was for tissue-specific expression of Amy in adult midguts; a total of 13 different patterns of activity have been observed. The preceding paper (Powell and Lichtenfels 1979) reports evidence that the variation in Amy expression is under polygenic control. Here we show that the polymorphism for midgut patterns occurs in natural populations and is not an artifact of laboratory rearing.--From population to population, Amy allele frequencies and frequencies of inversions belonging to different phylads vary coordinately. The geographic variation in alpha-amylase midgut activity patterns is uncorrelated with that for the other two types of polymorphisms. Furthermore, no correlation was detected between activity pattern(s) and Amy genotype(s) when both were assayed in the same individual.--These results imply that whatever the evolutionary-ecological forces are that control frequencies of the structural gene variants, they are not the same factors that control the frequencies of polymorphic genetic factors responsible for the tissue-specific expression of the enzyme.
在果蝇的十个自然种群中，测定了三种相关多态性的形态频率。它们分别是第三条染色体上著名的倒位多态性，以及由结构基因Amy（位于第三条染色体上）产生的α-淀粉酶多态性。第三种多态性是Amy在成年中肠中的组织特异性表达；总共观察到了13种不同的活性模式。前文（鲍威尔和利希滕费尔斯，1979年）报道了证据表明Amy表达的变异受多基因控制。在这里我们表明，中肠模式的多态性存在于自然种群中，并非实验室饲养的人为产物。——在不同种群之间，Amy等位基因频率以及属于不同类群的倒位频率协同变化。α-淀粉酶中肠活性模式的地理变异与其他两种多态性的地理变异不相关。此外，当在同一个体中同时测定活性模式和Amy基因型时，未检测到它们之间的相关性。——这些结果意味着，无论控制结构基因变体频率的进化生态力量是什么，它们与控制负责该酶组织特异性表达的多态遗传因子频率的因素不同。
