用籼/籼交重组自交系群体构建的分子遗传图谱及其与籼/粳交群体的分子图谱的比较

为了最终实现对籼稻数量性状基因位点 (QTLs)精确定位 ,用一个包含 1 31个系的籼 /籼交重组自交系群体 (F6∶7)构建了分子遗传连锁图谱。该图谱含由 1 1 3个水稻探针、2 8个小麦探针揭示的 1 6 0个RFLP标记和由 5个PstⅠ /MseⅠ引物组合揭示的 78个AFLP标记。群体的杂合性比率接近期望值 ,表明该群体具有正常的遗传结构。在 6个染色体区域观察到标记的偏分离 ,表明即使在亚种内群体中也可能发生标记的偏分离。本图谱的总长度为 1 4 35 8cM ,相邻标记间的平均距离为 6 38cM。由于采用了一套日本水稻基因组计划 (RGP)的RFLP标记 ,使本图谱能与RGP图谱进行比较。结果表明 ,两个图谱上的共同标记所覆盖图谱总长度几乎相同 ;在水稻 1 2条染色体中的 9条表现完全的连锁保守性。此外 ,水稻的第 1号染色体与小麦的第 3组染色体具有很强共线性。但是 ,两个图谱间也存在明显的差异 ,在 1S、1L、4L和 8L 4个染色体臂上发现 4个小倒位 ;除第 5号和第 6号染色体外的其他染色体上共检测到 1 9个新的位点。籼稻亲本间在染色体臂 2S、7S、1 0L和 1 1S 4个区域的RFLP多态性很低或没有 ,从而导致籼稻图谱在这些区域呈现空白。在这个籼稻图谱中 ,未检测到第 1 1号和 1 2号染色体间的重复性。还就稻属在基因组进化中的染

A Molecular Map Based on an Indica/Indica Recombinant Inbred Population and Its Comparison with an Existing Map Derived from Indica/Japonica Cross in Rice

With the eventual purpose of precisely locating quantitative trait loci (QTLs) in indica rice, a molecular linkage map was constructed based on an indica × indica derived recombinant inbred (RI) population consisting of 131 (F6∶7) lines. The map consists of 160 RFLP markers detected by 113 rice and 28 wheat probes and 78 AFLP markers revealed by five PstⅠ/MseⅠ primer combinations. The heterozygosity rate of the population was close to the expectation, indicating that the population had a normal genetic structure. Segregation distortion was observed in six chromosomal regions, suggesting that abnormal segregation could happen even in an intra-subspecies population. The map covers a length of 1435.8 cM, with an average distance of 6.38 cM between adjacent markers. A set of RFLP landmarks generated by the Japanese Rice Genome Program (RGP) was applied to allow comparison between our map and the RGP map. Both maps have nearly the same total map length regarding the coverage by common markers. Nine of 12 chromosomes showed complete linkage conservation in the two maps and rice chromosome 1 represented strong linearity to wheat group 3 chromosomes. Distinct organization between the two maps was evident. Four small inversions in chromosome arms 1S, 1L, 4L and 8L and nineteen additional loci mapping to all twelve chromosomes except chromosomes 5 and 6 were detected. Four regions on chromosome arms 2S, 7S, 10L and 11S exhibited no, or at least very low polymorphism resulting in obvious distal deficiencies in these regions of the indica map. The conservation of duplicated fragments between chromosome 11 and 12 was not detected in the indica map. Chromosome rearrangement involving in genome evolution in O. sativa is discussed.