Xiong Zhi Yong, Tan Guang Xuan, He Guang Yuan, He Guang Cun, Song Yun Chun
Key Laboratory of the Ministry of Education for Plant Developmental Biology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
Cell Res. 2006 Mar;16(3):260-6. doi: 10.1038/sj.cr.7310033.
The genomic structures of Oryza sativa (A genome) and O. meyeriana (G genome) were comparatively studied using bicolor genomic in situ hybridization (GISH). GISH was clearly able to discriminate between the chromosomes of O. sativa and O. meyeriana in the interspecific F1 hybrids without blocking DNA, and co-hybridization was hardly detected. The average mitotic chromosome length of O. meyeriana was found to be 1.69 times that of O. sativa. A comparison of 4,6-diamidino-2-phenylindole staining showed that the chromosomes of O. meyeriana were more extensively labelled, suggesting that the G genome is amplified with more repetitive sequences than the A genome. In interphase nuclei, 9-12 chromocenters were normally detected and nearly all the chromocenters constituted the G genome-specific DNA. More and larger chromocenters formed by chromatin compaction corresponding to the G genome were detected in the hybrid compared with its parents. During pachytene of the F1 hybrid, most chromosomes of A and G did not synapse each other except for 1-2 chromosomes paired at the end of their arms. At meiotic metaphase I, three types of chromosomal associations, i.e. O. sativa-O. sativa (A-A), O. sativa-O. meyeriana (A-G) and O. meyeriana-O. meyeriana (G-G), were observed in the F1 hybrid. The A-G chromosome pairing configurations included bivalents and trivalents. The results provided a foundation toward studying genome organization and evolution of O. meyeriana.
利用双色基因组原位杂交（GISH）对水稻（A基因组）和南方野生稻（G基因组）的基因组结构进行了比较研究。在不使用封闭DNA的情况下，GISH能够清晰地区分种间F1杂种中水稻和南方野生稻的染色体，几乎检测不到共杂交现象。发现南方野生稻的有丝分裂染色体平均长度是水稻的1.69倍。4,6-二脒基-2-苯基吲哚染色比较表明，南方野生稻的染色体标记更广泛，这表明G基因组比A基因组扩增了更多的重复序列。在间期细胞核中，通常检测到9-12个染色中心，几乎所有染色中心都构成了G基因组特异性DNA。与亲本相比，在杂种中检测到更多且更大的由对应于G基因组的染色质压缩形成的染色中心。在F1杂种的粗线期，除了1-2条染色体在臂端配对外，A和G的大多数染色体彼此不联会。在减数分裂中期I，在F1杂种中观察到三种类型的染色体配对，即水稻-水稻（A-A）、水稻-南方野生稻（A-G）和南方野生稻-南方野生稻（G-G）。A-G染色体配对构型包括二价体和三价体。这些结果为研究南方野生稻的基因组组织和进化奠定了基础。
