Forty-two homozygous lines each isoallelic for the Esterase 6 (Est-6) locus were extracted from a natural population of Drosophila melanogaster. Homogenates of 4–5 day old virgin adults of each sex from several replicate cultures of each line were assayed for EST6 activity. Depending on the line, males had from three to nine times more EST6 activity than females. Both sexes showed highly significant differences in EST6 activity among lines, with 3·2 and 2·7 fold differences between highest and lowest lines for males and females respectively. However, the variation in EST6 activity among lines was only weakly correlated across the two sexes. Female EST6 activity did not differ significantly across the six electrophoretic variants of EST6 found among the 42 lines. On the other hand, a significant proportion of the variation among lines in male EST6 activity could be explained by differences among the six electromorphs. However, most of these differences were due to the relatively high activities of males from two relatively rare electromorphs and there were no significant differences in male activity among the four more common EST6 electromorphs. Radial immunodiffusion assays with polyclonal anti-EST6 antibody established that differences among lines in male EST6 activity were largely due to differences in the number of EST6 protein molecules, with negligible differences in their specific activities. It is concluded that the natural population segregates for genetic variance with large effects on the amount of EST6 protein; that there is little overlap in the variance expressed in the two sexes; and that most of the variance is different from the polymorphisms for electrophoretically detectable variants of EST6.

中文翻译：

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黑腹果蝇天然种群中酯酶6的数量和活性的变化

从黑腹果蝇的天然种群中提取了 42 个纯合品系，每个纯合品系的酯酶 6 (Est-6) 基因座都是等位基因。对来自每个品系的几个重复培养物的每个性别的 4-5 天大的原始成虫的匀浆进行了 EST6 活性分析。根据不同的品系，雄性的 EST6 活性是雌性的 3 到 9 倍。雌雄株系间EST6活性差异极显着，雄株和雌株最高株系和最低株系之间的差异分别为3·2和2·7倍。然而，株系之间 EST6 活性的变化在两种性别之间仅具有微弱的相关性。雌性 EST6 活性在 42 个品系中发现的六种 EST6 电泳变体之间没有显着差异。另一方面，雄性 EST6 活性品系之间的很大一部分变异可以用六个电形态之间的差异来解释。然而，这些差异中的大部分是由于来自两个相对稀有的电形态的雄性的相对较高的活性，而四种更常见的 EST6 电形态之间的雄性活性没有显着差异。使用多克隆抗 EST6 抗体的径向免疫扩散测定确定，雄性 EST6 活性的品系之间的差异主要是由于 EST6 蛋白分子数量的差异，而它们的比活性差异可以忽略不计。得出的结论是，自然种群因遗传变异而分离，对 EST6 蛋白的数量有很大影响；两性表达的方差几乎没有重叠；