Systematic study of evolution of sex-differentiation genes involved in speciation of Saccharomyces yeasts

为了阐明酵母的物种形成机制，我们尝试比较了几种酵母的性别分化基因和染色体组织。主要研究结果如下：1.从酵母菌Naganishii中分离到一个编码α交配信息素的基因。然后，我们将该基因的结构与来自酿酒酵母实验室菌株的同源基因进行了比较。结果，这两个基因的编码区极其相似。然而，这两个基因的5‘-上游调控区表现出物种特异性的差异。2.我们从一株同源类型的酵母菌株中分离到一个编码同源基因的基因。然后，我们将该基因的结构与来自酿酒酵母实验室菌株的同源基因进行了比较。结果表明，这两个基因的编码区和5‘-上游调控区在进化过程中是共同进化的。3.研究了Naganishii酵母半乳糖同化相关基因的染色体定位。结果表明，GAL10基因是从Naganishii基因组中的Gal基因中移位出来的。这是非常独特的，因为到目前为止，GAL10基因包括在GAL基因簇中的事实已被报道。

In order to clarify the mechanism of speciation in Saccharomyces yeasts, we attempted to compare sex-differentiation genes and chromosome organizations among several Saccharomyces yeasts. Research results we obtained are as follows.1.We isolated a gene encoding an alpha mating pheromone from the yeast Saccharomyces naganishii. Then, we compared the structure of the gene with that of an orthologue from a laboratory strain of the yeast Saccharomyces cerevisiae. As a result, the coding regions of these two genes extremely resembled each other. However, the 5'-upstream regulatory regions from these two genes represented species-specific divergence.2.We isolated a gene encoding a homothallism gene from a homothallic type strain of the yeast Saccharomyces paradoxus. Then, we compared the structure of the gene with that of an orthologue from a laboratory strain of the yeast Saccharomyces cerevisiae. As a result, it was shown that the coding regions and 5'-upstream regulatory regions from these two genes had coevolved through the evolutionary pathway.3.We investigated the chromosomal localization of genes involved in galactose assimilation in the yeast Saccharomyces naganishii. It was revealed that the GAL10gene was translocated from the duster of GAL genes in the S.naganishii genome. It is very unique because the fact that the GAL10 genes are included in the GAL gene clusters has been reported so far.