通过染色体步查建立水稻G200座位的重叠群

分别以G200及其旁侧区的Y2587L、Y4073L和L688片段为探针筛选水稻基因组YAC文库，共得到4个阳性克隆，均与G200、Y2587L和Y4073L座位重叠，插入片段的大小为240～650kb。用反向PCR法分离YAC克隆插入片段的末端序列，并利用这些末端序列确定克隆的方向以及进行染色体步查，共筛选到7个YAC克隆，建立了一个8厘摩(cM)的G200 YAC重叠群。

Construction of a YAC Contig Encompassing G200 Locus via Chromosome Walking

A YAC contig was constructed by screening a rice genomic YAC library with G200,Y2587L,Y4073L and L688 RFLP markers as probes.4 positive clones with the sizes ranged from 240kb to 650kb were obtained.The end fragments of YAC inserts were isolated via inverse PCR,with whom a YAC contig of 3cM was initially established.Chromosome walking was performed with the two distal end fragments of the YAC contig and some positive YAC clones were obtained and identified. Thus the G200 contig was extended to about 8cM.