DNA甲基化差异对猪生长性状的影响

Effects of DNA Methylation Difference Growth Traits

测定和计算了大白×梅山F1 个体180日龄活重、料肉比、日增重、90 kg日龄、相对生长率和(KR)Kleiber5个性状,应用甲基敏感扩增多态技术(MSAP)分析了DNA甲基化与以上生长性状的关系。共扩增出 1 274 个位点,其中在252个多态性位点中,有81个甲基化位点对生产性状产生显著的影响。整体上,亲子代间甲基化差异不显著。但是,经配对数据t检验分析,每对引物在亲子代间扩增的带数表现出一定的差异:梅山猪与F1 代的差异接近显著性标准,大白猪与F1 代的差异达到极显著(P<0 .05)。个体一般甲基化百分差异和个体中性甲基化百分差异对所研究的6个生长性状均无显著的效应(P>0. 05)。除180日龄活重外,个体特殊甲基化百分差异对其余5个性状均产生显著的效应(P<0 .05)。从有利于养猪生产力这一角度讲,5 个生长性状表现都随个体特殊甲基化百分差异的增加而下降。回归分析表明,个体特殊甲基化百分差异与 5 个性状回归关系显著(P<0. 05)。结果显示,DNA甲基化是影响杂种表现或杂种优势的因素之一,可以作为分子标记用于杂种优势的预测和相关的研究;对性状产生显著影响的甲基化位点在预测杂种表现中要优于其它甲基化位点。

In F 1 individuals of Large White × Meishan, weight of 180 days, ratio of feedstuff to meat, average daily gain and days for 90 kg living weight were tested, and relative growth ratio and Kleiber ratio were calculated. The relationship between DNA methyaltion and these growth traits were analyzed with methylation-sensitive amplified polymorphism (MSAP) technique. In all, 1 274 sites were amplified with 81 methylated sites significant effected on growth traits in 252 polymorphic sites (P<0.05). The number of overall cytosine sites between parental lines and hybrid F 1 were not singnificantly different, but the number of methylation sites amplified by each pair primers was significantly different(P<0.05). Results show that general and neutral individual methylation percentage differences didn’t significantly effect on performance of any growth traits, but special individual methylation percentage difference significantly effected on performance of Kleiber ratio, ratio of feedstuff to meat, average daily gain and days for 90 kg. Performances of the 5 growth traits all decreased as special individual methylation percentage difference (SIMPD) increased in view of improving pig productivity. The linear regression between SIMPD and values of 5 growth traits were significant. It can be concluded that DNA methylation can effects hybrid performance or heterosis and be used as DNA markes in predicting heterosis and related studies of pigs; methylated sites that significantly effect on a trait are superior to other methylated sites in predicting hybrid performance.