河八王杂交种F1、BC1及其亲本DNA甲基化水平和模式变化

DNA methylation levels and genetic patterns in Narenga porphyrocoma （Hance） hybrids F1, BC1 and their parental inbreds

为分析河八王及后代基因组DNA甲基化水平和遗传模式变化,以河八王及其后代F1和BC1为材料,采用甲基化敏感扩增多态性技术(Methylation sensitive amplification polymorphism,MSAP)结合毛细管电泳技术(Capillary electrophoresis,CE)分析亲本及后代基因组DNA甲基化水平和遗传模式变化规律。结果表明:母本‘GT05-3256’的MSAP比率是59.6%,父本‘GXN1’则是60.5%,其杂交种F1的MSAP比率是56.4%~59.0%,均低于双亲;BC1的母本‘YC94-46’的MSAP比率是59.4%,父本‘T6-3’则是59.0%,BC1MSAP比率是56.9%~69.8%,整体平均为62.8%,平均值高于双亲。BC1世代总甲基化水平略高于F1世代水平。F1和BC1基因组CCGG位点发生甲基化的方式整体上以内部胞嘧啶双链甲基化为主。在F1和BC1中均检测到70种甲基化类型,并进一步分为A、B、C、D和E等5大类,其中A类是亲本向杂交种的甲基化遗传类型;B类是去甲基化类型,表示杂交种相应于其亲本的甲基化减弱;C类是过或超甲基化类型,表示杂交种相应于其亲本的甲基化增强;D类是次甲基化类型,杂交后代甲基化水平比双亲均要低;E类为不定类型。结果显示,B、C、D、E是杂交种的甲基化变异类型;F1的甲基化遗传类型(A类)比例明显低于BC1,但变异类型B、C、D、E高于BC1;杂交形成F1和BC1过程中,基因组DNA普遍发生了超甲基化修饰。

In order to analyze the changes of DNA methylation level,the DNA methylation levels and genetic patterns in F1,BC1 and their parents were detected using methylation sensitive amplification polymorphism(MSAP)and capillary electrophoresis technology(CE).The results showed that:MSAP ratios in the maternal parent GT05-3256,paternal parent GXN1 and in the hybrid F1 were respectively 59.6%,60.5%and 56.4%-59.0%,showing the MSAP ratio in F1 was lower than that in the both parents;the MSAP ratios in the maternal parent YC94-46,paternal parent T6-3 and BC1 were respectively 59.4%,59.0%and 56.9%-69.8%in with the average of 62.8%,showing that the MASP ratio of BC1 was higher than that in the both parents.The total methylation level in the BC1 generation is slightly higher than that in the F1 generation;the methylation of CCGG loci in sugarcane genome of the individuals in F1 and BC1 mainly occurred on the internal cytosine double-strand.A total of 70 different methylations were detected in the F1 and BC1 populations,and they were further divided into 5 types:type A,the methylation patterns in the hybrids were the same as their parents;type B,demethylation,the methylation in the hybrids was weaken compared to that in the parents;type C,hypermethylation,the methylation in the hybrids was enhanced corresponding to the parents;type D,hypomethylation,the degree of methylation in the hybrids was lower than that in the both parents;and type E,uncertain type.Among them,type A is the genetic transfer type from the parent to the hybrid,and types B,C,D and E are the methylation variants of the hybrids.The results showed that the rate of methylation type A in the F1 individuals was significantly lower than that in the BC1 while types B,C,D,and E were higher than those in the BC1.In conclusion,during the F1 and BC1 hybridization,the hypermethylation occurred in the whole genome.