Rice W R
Department of Biology, University of California, Santa Cruz 95064.
Science. 1994 Jan 14;263(5144):230-2. doi: 10.1126/science.8284674.
Comparative studies suggest that sex chromosomes begin as ordinary autosomes that happen to carry a major sex determining locus. Over evolutionary time the Y chromosome is selected to stop recombining with the X chromosome, perhaps in response to accumulation of alleles beneficial to the heterogametic but harmful to the homogametic sex. Population genetic theory predicts that a nonrecombining Y chromosome should degenerate. Here this prediction is tested by application of specific selection pressures to Drosophila melanogaster populations. Results demonstrate the decay of a nonrecombining, nascent Y chromosome and the capacity for recombination to ameliorate such decay.
比较研究表明，性染色体最初是普通的常染色体，只是偶然携带了一个主要的性别决定基因座。在进化过程中，Y染色体被选择停止与X染色体重组，这可能是为了应对有利于异配性别但对同配性别有害的等位基因的积累。群体遗传学理论预测，不发生重组的Y染色体应该会退化。本文通过对黑腹果蝇种群施加特定的选择压力来检验这一预测。结果表明，一个新生的不发生重组的Y染色体会发生衰退，而重组有能力改善这种衰退。
