利用水稻C0t-1 DNA和基因组DNA对栽培稻、药用野生稻和疣粒野生稻基因组的比较分析

【目的】研究中高度重复序列在稻属不同物种基因组进化中的作用。【方法】用栽培稻C0t-1 DNA和基因组DNA(gDNA)作为探针，分别对栽培稻、药用野生稻和疣粒野生稻进行荧光原位杂交(FISH)和比较基因组杂交(CGH)。【结果】C0t-1 DNA覆盖栽培稻、药用野生稻和疣粒野生稻基因组比例(%)和大小(Mb)分别为47.10±0.16，38.61±0.13，44.38±0.13和212.33±1.21，269.42±0.89以及532.56±1.68。栽培稻gDNA在药用野生稻和疣粒野生稻基因组中的覆盖率约为91.0%和93.6%，含量分别约为634 Mb和1123 Mb，各有365 Mb和591 Mb不属于源自栽培稻基因组的中高度重复序列，未被栽培稻gDNA所覆盖的部分，分别为64 Mb和78 Mb左右。此外，以C0t-1 DNA的组成为依据，对这3个种核型进行了同源性聚类。【结论】稻属中度和高度重复序列和功能基因一样，在不同种中也存在着高度同源性和保守性，并在进化过程中得以保存下来。药用野生稻和疣粒野生稻基因组增大的重要原因之一，可能是基因组中度和高度重复序列加倍的结果，药用野生稻这种序列扩增相对疣粒野生稻要缓和得多。另外，这两个野生种在长期进化过程中，由于存在加倍、重排和基因选择性丢失等现象，形成了具有自己种的特异性的基因组成分。

Comparative Analysis of Oryza sativa, O. officinalis and O. meyeriana Genome with C0t-1 DNA and Genomic DNA

【Objective】The aim of the experimeut is to study what the role of highly and moderately repetitive DNA sequences is play during the evolution process among different genomes in genus Oryza.【Method】 Fluorescence in situ hybridization (FISH) procedure and comparative genomic hybridization (CGH) were adopted for genome analysis of Oryza sativa, O. officinalis and O. meyeriana with C0t-1 DNA and genomic DNA from cultivated rice as probes. 【Result】The coverage percentage (%) and size (Mb) of C0t-1 DNA in cultivated rice, O. officinalis and O. meyeriana were 47.10±0.16, 38.61±0.13, 44.38±0.13 and 212.33±1.21, 269.42±0.89 and 532.56±1.68, respectively. While the coverage percentage and size of genomic DNA from O. sativa in O. officinalis and O. meyeriana were 91.0%, 93.6% and 634 Mb, 1123 Mb respectively, in which there are 365 Mb and 591 Mb in O. officinalis and O. meyeriana which come from O. sativa genomic DNA not from repetitive sequences of O. sativa, and the uncoverage size in O. officinalis and O. meyeriana were 64 Mb and 78 Mb, respectively. In addition homologous category on karyotype analysis of these three species, O. sativa, O. officinalis and O. meyeriana, was made according to C0t-1 DNA content. 【Conclusion】The results showed that highly and moderately repetitive sequences in Oryza genus were conserved during evolution over millions of years in crop species as the functional genes. The repetitive sequences reduplication might be one of the important causes of the genome enlargement of O. officinalis and O. meyeriana. O. officinalis genome enlarged more slowly compared to O. meyeriana. Based on the above results, it is concluded that the duplication, recombination, and gene selective deletion formed the two species, O. officinalis and O. meyeriana during millions of years of evolution.