Analysis of gene conversions between tandem duplicated genes

我们已经测定了小鼠和大鼠Rh血型基因的完整编码区，以及小鼠、大鼠和食蟹猕猴的Rh相关50kD糖蛋白(Rh5O)的完整编码区。对Rh和Rh5O氨基酸序列的系统发育分析表明，在灵长类和啮齿动物中，Rh5O基因的进化速度大约是Rh血型基因的两倍。Rh5O基因的这种保守性表明它对Rh血型基因的相对重要性。据估计，产生Rh和Rh50基因的基因复制时间约为2.4亿-3.1亿年前。我们还对这两个基因的同义和非同义核苷酸替换进行了窗口分析。一些非同义取代高于同义取代的峰位于外膜区。这表明在Rh和Rh5O基因上存在通过宿主-寄生虫相互作用的正达尔文选择。

We have sequenced the complete coding region of the Rh blood group gene for mouse and rat and that of Rh-related 50kD glycoprotein (Rh5O) for mouse, rat, and crab-eating macaque. Phylogenetic analyses of Rh and Rh5O amino acid sequences indicate that the Rh5O gene has been evolving about two times more slowly than the Rh blood group gene both in primates and rodents. This conservative nature of the Rh5O gene suggests its relative importance to the Rh blood group gene. The time of gene duplication that produced the Rh and Rh50 genes was estimated to be about 240-310 million years ago. We also conducted window analyses of synonymous and nonsynonymous nucleotide substitutions for those two genes. Some peaks where nonsynonymous substitutions are higher than synonymous ones were located on outer membrane regions. This suggests the existence of positive Darwinian selection on Rh and Rh5O genes through host-parasite interactions.