Substitution rates in the X- and Y-linked genes of the plants, Silene latifolia and S-dioica
Substitution rates in the X- and Y-linked genes of the plants, Silene latifolia and S-dioica
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DOI：
10.1093/oxfordjournals.molbev.a004147
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发表时间：
2002-06-01
影响因子：
10.7
通讯作者：
Charlesworth, D
中科院分区：
文献类型：
--
作者：
Filatov, DA;Charlesworth, D
理论预测，相对于其他染色体上的基因，选择在Y染色体上的非重组基因中的效果应该较低，这应该导致有害的非同义替换的积累。此外，由于男性驱动的进化效应，以及性染色体之间每次复制突变率的实际差异，X和Y连锁基因之间的同义替换率可能不同。在这里，我们报告了植物性染色体上的同义和非同义置换率的第一次研究。我们测序了两对性连锁基因。SlX_1-SlY_1和SlX_4-SlY_4分别来自雌雄异株的宽叶蝇子草（Silene latifolia）和宽叶蝇子草（S. dioica和非雌雄异株S. vulgaris和剪秋罗。SlY 4基因的非同义替换率显著高于SlX 4基因。沉默替代率也显着较高的Y连锁，的。与它们的X连锁同源物相比。因此，SlY 4基因中较高的非同义替换率可能是由性染色体之间的突变率差异引起的。SlX 4和SlY 4基因之间沉默替换率的差异太大，不能仅仅用雄性比雌性更高的每代突变率来解释。因此，它可能是由性染色体之间的重复突变率差异引起的。这表明局部突变率可以在相对较短的进化时间内发生变化。
Theory predicts that selection should be less effective in the nonrecombining genes of Y-chromosomes, relative to the situation for genes on the other chromosomes, and this should lead to the accumulation of deleterious nonsynonymous substitutions. In addition, synonymous substitution rates may differ between X- and Y-linked genes because of the male-driven evolution effect and also because of actual differences in per-replication mutation rates between the sex chromosomes. Here, we report the first study of synonymous and nonsynomynous substitution rates on plant sex chromosomes. We sequenced two pairs of sex-linked genes. SlX1-SlY1 and SlX4-SlY4, from dioecious Silene latifolia and S. dioica, and their non-sex-linked homologues from nondioecious S. vulgaris and Lychnis flosjovis, respectively. The rate of nonsynonymous substitutions in the SlY4 gene is significantly higher than that in the SlX4 gene. Silent substitution rates are also significantly higher in both Y-linked,ones. compared with their X-linked homologues. The higher nonsynonymous substitution rate in the SlY4 gene is therefore likely to he caused by a mutation rate difference between the sex chromosomes. The difference in silent substitution rates between the SlX4 and SlY4 genes is too great to be explained solely by a higher per-generation Mutation rate in males than females. It is thus probably caused by a difference in per-replication mutation rates between the sex chromosomes. This suggests that the local mutation rate can change in a relatively short evolutionary time.