草鱼全同胞鱼苗不同个体甲基化位点的差异

本研究通过甲基化敏感扩增多态性(Methylation sensitive amplification polymorphism)对一对草鱼亲本的20个子代甲基化位点进行了研究。从20对引物组合中扩增出311个位点,其中甲基化位点236个,占总扩增位点的75.9%,表明草鱼水花期基因组甲基化水平已经很高,说明它们大部分组织分化基本完成;其中甲基化多态位点65个,占甲基化位点的27.5%,说明这些子代草鱼甲基化位点已经有相当的差异。对其他两对亲本的后代用六个引物组合扩增的结果表明,同一亲本的子代在甲基化模式上有差异可能是普遍现象。本研究结果说明,即使来自同一对草鱼亲本的不同子代个体在基因表达上也有较大的差异,因此很多性状在草鱼后代的分离和一些基因表达的改变有一定的关系。

Differences in methylated loci among different grass carp individuals from one pair of parents

This study aims to investigate the effect of breeding on epigenetic diversity in grass carp Ctenopharyngodon idella. The researchers believe that the genetic diversity decreases after artificial breeding for several generations. But the distinct changes in phenotype could also be observed in members of the same families with either great or little decreases in genetic diversity. It is likely that in addition to genetic diversity some other factors may contribute to phenotypic changes. Differences of the genomes include differences in nucleotide sequence and epigenetic modification. In particular, differential DNA methylation plays an important role in gene expression regulation during development and growth of vertebrates. Thus, we expect that study on methylation differentiation in F1 generation would provide novel insight into mechanisms of phenotypic variation. For this purpose, three F1 families of grass carp, each consisting of 20 individuals, were collected in May 2006 and 2007. Methylation sensitive amplified polymorphism (MSAP) was used to analyze the difference of methylation status between individuals. With 20 primer combinations, 311 amplified loci were identified from the family collected in 2006, of which 236 loci (about 75.9%) were methylated, suggesting a high methylation level. 27.5% of the methylated loci were polymorphic, implying that the expression of some genes might be differentially expressed among these individuals. The other two families, collected in 2007, were also analyzed with 6 primer combinations, and polymorphic methylated loci were also detected. The results indicate that different offsprings of the same parents display differential methylation patterns. It also show that phenotypic changes may be related to the differential methylation and ultimately affects on the gene expression.