Coen E S, Thoday J M, Dover G
Nature. 1982 Feb 18;295(5850):564-8. doi: 10.1038/295564a0.
A high degree of polymorphism for the length and copy number of rDNA spacers, in both the X and Y chromosome clusters, has been found in a wild population of Drosophila melanogaster. The genetic behaviour of rDNA structural variants in separate and mixed populations derived from isofemale lines suggest that they are not subject to strong selection and are stable for over 1,000 generations. The high structural variability suggests an evolutionary rapid process of turnover in the family which could partly explain widespread sequence homogeneity (concerted evolution) of rDNA within a species.
在黑腹果蝇的一个野生种群中，已发现X和Y染色体簇中rDNA间隔区的长度和拷贝数存在高度多态性。来自同雌系的单独和混合种群中rDNA结构变体的遗传行为表明，它们不受强烈选择，并且在1000多代中保持稳定。高度的结构变异性表明该家族中存在快速的进化周转过程，这可以部分解释物种内rDNA广泛的序列同质性（协同进化）。
