The extent and patterns of cytosine methylation in blood DNA were assessed, using thetechnique of methylation-sensitive amplified polymorphism(MSAP),in Meishan, Large White pigsand hybrids of their reciprocal crosses....The extent and patterns of cytosine methylation in blood DNA were assessed, using thetechnique of methylation-sensitive amplified polymorphism(MSAP),in Meishan, Large White pigsand hybrids of their reciprocal crosses. In all, 1 508 fragments, each representing a reco-gnition site cleaved by either or both of the isoschizomers, MspI and HpaII, were amplifiedusing 20 pairs of selective primers. 10.3% of CCGG sites were methylated in Meishan pigs, 10.5%in Large White pigs, and 10.2% in the hybrids. Cytosine methylation was not significantlydifferent among parental lines and hybrids of reciprocal crosses. Four classes of patternswere identified in a comparative assay of cytosine methylation in the parents and hybrids: (1)the same level of methylation in both parental lines and the hybrids; (2) the same level ofmethylation in either parent or hybrid; (3) an increased level of methylation in the hybridscompared to the parents, and (4) a decreased level of methylation in the hybrids. 11 cross-specific methylation sites were detected in F1 hybrids of Large White ×Meishan, and 10 cross-specific methylation sites in the hybrid of Meishan ×Large White. In conclusion, (1) the wholemethylation status between parental lines and hybrids was not different, but specific siteswere differentially methylated; (2) specific sites were differentially methylated betweenreciprocal crosses; (3) demethylation and hypermethylation of many sites accounted for mostly(more than 50%) methylated sites in the hybrids compared to parental lines.展开更多
文摘The extent and patterns of cytosine methylation in blood DNA were assessed, using thetechnique of methylation-sensitive amplified polymorphism(MSAP),in Meishan, Large White pigsand hybrids of their reciprocal crosses. In all, 1 508 fragments, each representing a reco-gnition site cleaved by either or both of the isoschizomers, MspI and HpaII, were amplifiedusing 20 pairs of selective primers. 10.3% of CCGG sites were methylated in Meishan pigs, 10.5%in Large White pigs, and 10.2% in the hybrids. Cytosine methylation was not significantlydifferent among parental lines and hybrids of reciprocal crosses. Four classes of patternswere identified in a comparative assay of cytosine methylation in the parents and hybrids: (1)the same level of methylation in both parental lines and the hybrids; (2) the same level ofmethylation in either parent or hybrid; (3) an increased level of methylation in the hybridscompared to the parents, and (4) a decreased level of methylation in the hybrids. 11 cross-specific methylation sites were detected in F1 hybrids of Large White ×Meishan, and 10 cross-specific methylation sites in the hybrid of Meishan ×Large White. In conclusion, (1) the wholemethylation status between parental lines and hybrids was not different, but specific siteswere differentially methylated; (2) specific sites were differentially methylated betweenreciprocal crosses; (3) demethylation and hypermethylation of many sites accounted for mostly(more than 50%) methylated sites in the hybrids compared to parental lines.
