|Budget Amount *help
¥9,500,000 (Direct Cost : ¥9,500,000)
Fiscal Year 1999 : ¥4,700,000 (Direct Cost : ¥4,700,000)
Fiscal Year 1998 : ¥4,800,000 (Direct Cost : ¥4,800,000)
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.