用水稻BAC克隆21K19作探针进行了ISH.这个克隆是由第4染色体着丝粒连锁的RFLP标记RZ69筛选得到.在Cot-l DNA 封阻条件下,DAB均获得第4染色体着丝粒区和间期染色质上的一对信号.这一方法不仅可用于特定染色体识别,而且可区分其长臂和短臂.因此,还获得了第四染色体的臂比值以作为它的形态识别依据.由于RFLP标记RZ69与抗性基因Bph3紧密连锁,从而确定抗性基因Bph3位于水稻第4染色体着丝粒处.相对于常规的RFLP-FISH,BAC-ISH可以提高5倍以上的检出率.%Rice chromosome 4 was identified by ISH of centromere-linked BAC clone 21K19. This clone was screened by a single copy RFLP marker RZ69. It only showed a pair of signal spots on centromere regions of each member of one chromosome pair, i.e.,chromosome 4 as well as interphase chromatin under the blocking of rice Cot-1 DNA with DAB detection system. This is applicable not only for the recognizing of chromosome 4 but also for the distinguishing of its long and short arms. Therefore, we also obtained the arm ratio data of chromosome 4 for its morphological identification. From the molecular genetic map, we know that the RZ69 linked to resistance gene, Bph3, so in this study, resistance gene, Bph3 was physical located in centromere region of chromosome 4 in Oryza. sativa.Compared with the routine FISH of single copy RFLP marker can increase the detection rate more than five times.
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