DNA甲基化在真核生物的生长发育过程中起着重要的调控作用.为了解水稻同源四倍体与二倍体之间的基因组及甲基化修饰差异,探究二倍体与同源四倍体的遗传差异和基因组DNA甲基化水平及模式变化,以冈46B、明恢63、绵恢725、成恢149、海天、什香6个二倍体水稻及相应的6个同源四倍体水稻为材料,采用微卫星分子标记技术(SSR)及甲基化敏感扩增多态性(Methylation-sensitive amplification polymorphism,MSAP)分析等方法进行研究.SSR结果显示,所试同源四倍体水稻的基因组与二倍体水稻基因组大部分相同,采用的引物中有3对引物多态性较好,在不同倍性水稻间扩增出特异性条带.经不同倍性甲基化水平分析,同源四倍体材料的平均总甲基化率(24.0%)明显低于二倍体材料的平均总甲基化率(28.15%).两个倍性材料间的全甲基化与半甲基化差异也较大:二倍体材料的全甲基化率平均为6.24%,半甲基化率平均为22.03%;同源四倍体水稻材料全甲基化率平均为7.44%,半甲基化率平均为16.61%.甲基化程度并未因多倍化而增加,这说明同一品种水稻的二倍体与同源四倍体间的DNA发生了甲基化修饰变化.进一步对不同倍性水稻DNA甲基化模式的变化特征进行分析,结果显示同源四倍体水稻中平均约有11.6%发生了去甲基化,平均约有24.11%位点发生了过甲基化,过甲基化基因的比例显著高于去甲基化的比例.研究表明同源四倍体水稻可能通过对一些功能基因的甲基化不表达,以缓和基因组加倍剂量效应造成的影响. DNA methylation plays an important regulatory role in the growth and development of eukaryotes.In order to understand the genomic and methylation differences between tetraploids and diploids in rice, Tetraploid genetic differences and genomic DNA methylation levels and pattern changes to Gang 46B, Minghui 63, Mianhuai 725, Chenghui 149, Haitian, Shixiang six diploid rice and the corresponding six homologous The tetraploid rice was used as material, and microsatellite markers (SSR) and methylation-sensitive amplification polymorphism (MSAP) The genome of the ploidy rice is mostly the same as that of the diploid rice genome, and three pairs of primers have good polymorphism, and specific bands are amplified in different ploidy rice. After different ploidy methylation In the horizontal analysis, the average total methylation rate (24.0%) of autotetraploid materials was significantly lower than that of diploid materials (28.15%). The methylation of two ploidy materials The difference with hemomethylation was also large: the average methylation rate of diploid material was 6.24% The average rate of methylation was 22.03%. The average rate of full methylation of autotetraploid rice was 7.44% and the average rate of methylation was 16.61%. The degree of methylation was not increased by polyploidization Indicating that the same species of rice diploid and autotetraploid DNA methylation changes occur.Different ploidy DNA methylation patterns of the characteristics of the analysis showed that the autotetraploid rice About an average of 11.6% demethylation occurs, an average of about 24.11% of the site has been hypermethylated, the proportion of hypermethylation gene was significantly higher than the proportion of demethylation studies have shown that four times the homology Inbred rice may be through the lack of methylation of some of the functional genes in order to alleviate the impact of genome doubling dose effect.