Phylogenetic analysis of Brassicaceae plants and molecular evolution of self-incompatibility

以19种十字花科植物为研究对象，测定了SLR1 （S-locus related gene 1）、rbcL （RuBisCO大亚基）和Plastid亚型ID的核苷酸序列，并进行了系统发育分析。SLR1分析结果表明，黑芸苔与甘蓝、油菜同属，但亲缘关系较远，而黑芸苔和莴苣与甘蓝、油菜亲缘关系较近。rbcL和质体亚型ID的分析表明，这些物种可分为B. rapa和B. rapa两类。马齿苋组和白刺/B组。认为黑螺旋藻与甘蓝有远亲关系。我们现在正在研究这些基因的种内变异，并打算计算这些物种形成的年份。在比较甘蓝、油菜和甘蓝型油菜的SLG和SRK基因（决定自交不亲和的自我/非自我识别特异性）时，发现了一组高度相似的等位基因。这组等位基因被认为在这三个物种形成之前是相同的等位基因。sativus的SLG等位基因并未与芸苔属形成独立的群体，表明S位点的多样化发生在这两个属分离之前。对S位点长DNA片段的分析表明，S位点复合体中DNA片段的插入或缺失发生在物种形成时或形成后。

Using 19 species of Brassicaceae plants, we determined nucleotide sequences of SLR1 (S-locus related gene 1), rbcL (Large subunit of RuBisCO), and Plastid subtype ID, and compared them for phylogenetic analysis. Analysis of SLR1 showed that Brassica nigra is distantly related to Brassica oleracea and Brassica rapa though they belong to the same genus, and that Erucastrum abyssinicum and Raphanus sativus are more closely related to B. oleracea and B. rapa. Analyses of rbcL and Plastid subtype ID indicated that these species can be separated into two groups, B. rapa/B. oleracea group and Sinapis alba/B. nigra group, and that B. nigra is distantly related to B. oleracea. We are now investigating the intra-specific variation of these genes, and going to calculate the year of speciation of these species.In the comparison of SLG and SRK genes, which determine the self/non-self recognition specificity of self-incompatibility, highly similar set of alleles among B. oleracea, B. rapa, and B. napus were found. This set of alleles are considered to have been the same allele before the speciation of these three species. SLG alleles of R. sativus did not form a group independent from those of Brassica, indicating that diversification of S locus occurred before the separation of these genus. Analysis of long DNA fragments of S locus suggested that insertion or deletion of DNA fragments occurred in the S locus complex at the time of or after the speciation.