Pamilo P, Bianchi N O
Department of Genetics, Uppsala University, Sweden.
Mol Biol Evol. 1993 Mar;10(2):271-81. doi: 10.1093/oxfordjournals.molbev.a040003.
A phylogenetic analysis of sex-chromosomal zinc-finger genes (Zfx and Zfy) indicates that the genes have not evolved completely independently since their initial separation. The sequence similarities suggest gene conversion in the last exon between the duplicated Y-chromosomal genes Zfy-1 and Zfy-2 in the mouse. There are also indications of conversion (or recombination) between the X- and Y-chromosomal genes in the crab-eating fox and in the mouse. The method for estimating synonymous and nonsynonymous substitutions is modified by incorporating the substitutions in the twofold-degenerate sites in a novel way. The estimates of synonymous substitutions support the generation-time hypothesis in that the obtained rates are higher in mice (by a factor of 4.7) than in humans and higher in the Y-chromosomal genes (by a factor of 1.9) than in the X-chromosomal genes.
对性染色体锌指基因（Zfx和Zfy）的系统发育分析表明，自最初分离以来，这些基因并未完全独立进化。序列相似性表明，小鼠中重复的Y染色体基因Zfy-1和Zfy-2的最后一个外显子存在基因转换。在食蟹狐和小鼠的X染色体与Y染色体基因之间也有转换（或重组）的迹象。通过以一种新的方式纳入两倍简并位点中的替换，对同义替换和非同义替换的估计方法进行了修改。同义替换的估计结果支持世代时间假说，因为在小鼠中获得的替换率（高出4.7倍）高于人类，且在Y染色体基因中（高出1.9倍）高于X染色体基因。
