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摘要：基因组DNA甲基化对基因表达起着重要的调控作用。本研究采用MSAP方法，对2个玉米杂交种及其相应亲本DNA 5’-CCG G位点胞嘧啶的甲基化水平进行分析，比较了2个玉米杂交种与其相应亲本的甲基化类型与差异。研究发现，2个玉米杂交种Mo17×Suwan 5和Suwan 1×太3221的F1代的甲基化敏感扩增多态性(MASP)比率分别为39．1％和40．1％，均略低于其相应的双亲(39．8％和39．7％、44．6％和43．2％)。2个杂交种的全甲基化(双链CmCGG)率分别为24．4％和23．3％，而其相应亲本Mo17、Suwan 5、Suwan 1和太3221分别为17．1％，24．4％、24．6％和21．6％。4个玉米亲本的MASP比率变化范围为39．7％-44．6％，平均为41．8％。全甲基化比率为17．1％-24．6％，平均为21．9％。杂交种与其相应亲本比较有4种类型的变化：A型，F1与其亲本甲基化横式相同；B型，去甲基化1C型，超甲基化；D型，次甲基化。杂交种F1代DNA的甲基化模式与其双亲比较，发生了较大的改变与调整。F1代基因组的杂合性与基因组DNA甲基化模式的重新调整有关。
Abstract: Genomic DNA methylation plays an important regulatory role in gene expression. In this study, MSAP method was used to analyze the methylation level of cytosine at the 5’-CCG G site of two maize hybrids and their corresponding parents. The methylation patterns of two maize hybrids and their corresponding parents were compared difference. The results showed that the methylation-sensitive amplification polymorphism (MASP) ratios of F1 progeny of two maize hybrids, Mo17 × Suwan 5 and Suwan 1 × Ta 3221, were 39.1% and 40.1%, respectively, both slightly lower In their corresponding parents (39.8% and 39.7%, 44.6% and 43.2%). The total methylation (double-stranded CmCGG) rates of the two hybrids were 24.4% and 23.3%, respectively, while the corresponding parents Mo17, Suwan 5, Suwan 1 and Ta 3221 were 17.1% and 24 respectively. 4%, 24.6% and 21.6%. MASP ratio of 4 maize parents ranged from 39.7% to 44.6% with an average of 41.8%. The full methylation ratio was 17.1% -24.6% with an average of 21.9%. There were 4 types of changes in hybrids and their corresponding parents: type A, F1 had the same methylation level as its parent; type B, demethylated type 1C, hypermethylated; type D, methylated. The methylation patterns of F1 hybrid DNA in hybrids were greatly changed and adjusted compared with their parents. The heterogeneity of the F1 generation genome is related to the readjustment of genomic DNA methylation patterns.