Marín I, Franke A, Bashaw G J, Baker B S
Department of Biological Sciences, Stanford University, California 94305, USA.
Nature. 1996 Sep 12;383(6596):160-3. doi: 10.1038/383160a0.
In species where males and females differ in number of sex chromosomes, the expression of sex-linked genes is equalized by a process known as dosage compensation. In Drosophila melanogaster, dosage compensation is mediated by the binding of the products of the male-specific lethal (msl) genes to the single male X chromosome. Here we report that the sex- and chromosome-specific binding of three of the msl proteins (MSLs) occurs in other drosophilid species, spanning four genera. Moreover, we show that MSL binding correlates with the evolution of the sex chromosomes: in species that have acquired a second X chromosome arm because of an X-autosome translocation, we observe binding of the MSLs to the 'new' (previously autosomal) arm of the X chromosome, only when its homologue has degenerated. Moreover, in Drosophila miranda, a Y-autosome translocation has produced a new X chromosome (called neo-X), only some regions of which are dosage compensated. In this neo-X chromosome, the pattern of MSL binding correlates with the known pattern of dosage compensation.
在雄性和雌性性染色体数量不同的物种中，性连锁基因的表达通过一种称为剂量补偿的过程实现均衡。在黑腹果蝇中，剂量补偿是由雄性特异性致死（msl）基因的产物与单条雄性X染色体结合介导的。我们在此报告，三种msl蛋白（MSLs）的性别和染色体特异性结合发生在其他果蝇科物种中，涵盖四个属。此外，我们表明MSL结合与性染色体的进化相关：在因X-常染色体易位而获得第二条X染色体臂的物种中，只有当同源染色体退化时，我们才观察到MSLs与X染色体的“新”（以前是常染色体）臂结合。此外，在拟果蝇中，Y-常染色体易位产生了一条新的X染色体（称为新X染色体），其中只有一些区域进行了剂量补偿。在这条新X染色体中，MSL结合模式与已知的剂量补偿模式相关。
