杨树三倍体与二倍体DNA甲基化的比较分析

利用甲基化敏感扩增多态性技术,对二倍体与三倍体黑杨和白杨群体DNA甲基化进行了研究,共检测到745个基因位点,不同倍性杨树群体基因组DNA的总甲基化率为13.69% 18.84%,二倍体杨树平均为14.71%,三倍体杨树平均为17.72%。不同倍性杨树种群总甲基化率随着倍性的升高而升高,半甲基化率黑杨组也随着倍性的升高而升高,而白杨组正好相反;黑杨组全甲基化率没有明显的规律可循,而白杨组的全甲基化率则随着倍性的升高而升高。倍性与甲基化率的相关性验证分析结果表明:总甲基化率与倍性的相关系数为0.835,P<0.01,总甲基化率与倍性呈极显著正相关;全甲基化率与倍性的相关系数为0.651,P<0.05,全甲基化率与倍性呈显著正相关;半甲基化率与倍性的相关系数为0.335,P>0.05,半甲基化率与倍性相关性较弱。不同倍性杨树群体的甲基化变异与序列变化具有显著相关性(r=0.910 3,P<0.01),推测甲基化变异具有种群特异性。

Detection of the DNA Methylation Difference Between the Triploid and Diploid Poplar Trees

The methylation-sensitive amplification polymorphism (MSAP) was used to analyze the methylation in triploid and diploid poplar trees. 745 loci were detected by gel electrophoresis. The total methylation ratios in different ploidy of poplar trees varied from 13.69% to 18.84%. And the average total methylation ratios were 14.71% for diploid and 17.72% for triploid trees. The total methylation rate of poplar populations increased with the ploidy, the semi-methylation in black poplar group also increased with the ploidy, while the opposite result was found in white poplar group. No regular pattern was found in the variation of total methylation ratios of black poplar group, and the total methylation rate of white poplar group increased with the ploidy. There exists a correlation between total methylation ratios and polyploidy level in poplar ploidy group (r=0.835, P<0.01). Also, a significant positive correlation was found between the fully methylation ratios and polyploidy level (r=0.651, P<0.05). But no significant correlation between hemimethylation ratios and polyploidy level was observed.