大白菜和结球甘蓝基因组原位杂交及核型分析

为研究A、C基因组间的亲缘关系和识别不同染色体，分别以大白菜（AA）和结球甘蓝（BB）的基因组总DNA为探针，与大白菜和结球甘蓝的中期染色体杂交。结果表明，两种基因组总DNA在大白菜20条染色体和结球甘蓝18条染色体上都有杂交信号，但信号图型有明显差异。大白菜基因组总DNA在大白菜和结球甘蓝染色体上的杂交信号几乎都只集中于近着丝粒区和核仁组织区，但在大白菜染色体上的分布区域略大；结球甘蓝基因组总DNA在其染色体上的杂交信号分散布满其全长，但在着丝粒区和核仁组织区显示增强的信号带，而在大白菜中期染色体上则主要集中于着丝粒和近着丝粒区，且强度弱于大白菜基因组总DNA为探针的杂交信号。基于大白菜基因组DNA的GISH信号对大白菜和结球甘蓝的核型进行了分析。该研究结果为鉴别其种间杂种及其染色体的组成和同源关系提供了分子细胞学依据。

Karyotype Analysis of Chinese Cabbage and Cabbage by Genome in Situ Hybridization

In order to study the relationship and identify different chromosomes between the A and C genome of Brassica, the labeled genomic DNAs of Chinese cabbage and cabbage were respectively hybridized to their metaphase chromosomes. Nonuniform distribution of the fluorescent labeled probe DNAs were observed on all the chromosomes of two species tested. The signal patterns varied between species and were related to the genome DNA probes. When Chinese cabbage genomic DNA was used as probe, the signals were almost only in the pericentromeric regions and the nucleolus organizer regions(NORs) of Chinese cabbage and cabbage, but the signal regions were larger in former than latter. While cabbage genomic DNA was used as probe, the signals dispersed along the chromosome lengths of cabbage and enhanced signal bands were shown in all pericentromeres and the NORs; Only were observed in the pericentromeres and the NORs of Chinese cabbage chromosomes, and that all the signal intensity was weaker than with genomic DNA probes of Chinese cabbage. Karyotypes of Chinese cabbage and cabbage were analyzed based on GISH signals. The results provided a molecular cytological basis for identification of interspecific hybrids, their chromosomic components and homologous between A and C genomes.