甘蓝rDNA及C0t-1 DNA荧光原位杂交及其核型分析

为了探索一种高效可靠的芸薹属植物核型分析方法，本文以甘蓝品种黑叶小平头为实验材料，从其基因组DNA中分离出C0t-1 DNA并用生物素标记作探针，对有丝分裂中期相染色体进行原位杂交，每对染色体上均显示出了特定的荧光原位杂交带型．将植物25S和5SrDNA分别用地高辛和生物素标记作探针，单色荧光原位杂交结果显示黑叶小平头2对染色体具有25SrDNA基因座，1对染色体具有5S rDNA基因座．生物素标记的C0t-1 DNA与地高辛标记的25S rDNA等量混合作探针，双色荧光原位杂交证实了C0t-1 DNA与25S rDNA二者具有一致的染色体位置特征，表明基于rDNA及C0t-1 DNA荧光原位杂交的核型分析技术，优于目前普遍采用的只基于rDNA荧光原位杂交的核型分析方法．结合已报道的rDNA染色体定位结果，及C0t-1 DNA荧光原位杂交带型与染色体形态，更准确地构建了甘蓝的核型．

Karyotyping of Brassica oleracea L. Based on rDNA and C0t-1 DNA Fluorescence in situ Hybridization

To explore an effective and reliable karyotyping method in Brassica crop plants,C_0t-1 DNA was isolated from Brassica oleracea genome,labeled as probe with Biotin-Nick Translation Mix kit,in situ hybridized to mitotic spreads,specific fluorescent bands were showed on each chromosome pairs.25S and 5S rDNA were labeled as probes with DIG-Nick Translation Mix kit and Biotin-Nick Translation Mix kit,respectively,in situ hybridized to mitotic preparations,25S rDNA could be detected on two chromosome pairs,and 5S rDNA only one.C_0t-1 DNA contains rDNA,chromosome sites identity between C_0t-1 DNA and 25S rDNA was determined by dual-colour fluorescence in situ hybridization.All these showed that the karyotyping technique based on a combination of rDNA and C_0t-1 DNA chromosome landmarks is superior to alone one. A more exact karyotype of B.oleracea have been analysed based on a combination of rDNA sites,C_0t-1 DNA fluorescent bands,chromosome lengths and arm ratios.