Mukai T, Harada K, Yoshimaru H
Genetics. 1984 Jan;106(1):73-84. doi: 10.1093/genetics/106.1.73.
In a marked-inversion balanced lethal system of the second chromosome of Drosophila melanogaster, mutations were accumulated under minimum pressure of natural selection in 1000 individual lines that originated essentially from two individuals. After about 300 generations, the specific activities of alcohol dehydrogenase of 69 randomly selected individual lines were measured with replications using four replicated vials (on 2 days--two replications per day) by observing the reduction of NAD+ to NADH at 340 nm. Total soluble protein as the basis of standardization of enzyme activity was measured by the Lowry method for each vial. A control experiment was made immediately after the establishment of 20 individual lines from a single genotype. A significant increase in genetic variance was observed among the mutation-accumulating lines but was not detected in the control experiment. The statistical analysis of the data on the basis of the one-band/one-gene hypothesis suggests that many mutations controlling the activity of alcohol dehydrogenase occurred in regions different from the alcohol dehydrogenase locus itself, mainly in the noncoding DNA. Furthermore, it is suggested that transposon-like elements are related to the induction of these changes in alcohol dehydrogenase specific activities. Additional experimental evidence supporting this conclusion is also given.
在果蝇黑腹果蝇第二染色体的一个标记倒位平衡致死系统中，在基本上源自两个个体的1000个单株系中，在自然选择的最小压力下积累突变。经过约300代后，通过观察340nm处NAD⁺向NADH的还原，使用四个重复小瓶（在2天内 - 每天两个重复）对69个随机选择的单株系的乙醇脱氢酶的比活性进行重复测量。通过Lowry法对每个小瓶测量作为酶活性标准化基础的总可溶性蛋白。在从单一基因型建立20个单株系后立即进行对照实验。在积累突变的株系中观察到遗传方差显著增加，但在对照实验中未检测到。基于单带/单基因假设对数据进行的统计分析表明，许多控制乙醇脱氢酶活性的突变发生在与乙醇脱氢酶基因座本身不同的区域，主要在非编码DNA中。此外，有人提出转座子样元件与乙醇脱氢酶比活性的这些变化的诱导有关。还给出了支持这一结论的其他实验证据。
