Polymorphisms and DNA methylation level in the CpG

Authors: J L Zhao Y F Si F He H S Wen J F Li Y Y Ren M L Zhao Z J Huang S L Chen

Publish Date: 2015/04/17

Volume: 41, Issue: 4, Pages: 853-865

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Abstract

The objectives of the present study were to estimate the GHR1 gene mutations and methylation status of CpGs and whether those mutations and methylation were involved in the regulation of GHR1 gene expression hormone level and growth traits in halfsmooth tongue sole Cynoglossus semilaevis Identification of singlenucleotide polymorphisms was performed on 43 male fish Through polymerase chain reactionsinglestrand conformation polymorphism and sequencing two SNPs were found SNP1 cG1357A pVal376Ile creating one CpG site located in exon 8 was named L1 locus and SNP2 cG1479A located in exon 9 was named L2 locus Individuals were divided into three genotypes AA AG and GG according to L1 locus GG genotype had one more CpG site because of the mutation and into two genotypes AA and GGbased on L2 locus The results showed that only L1 locus was significantly associated with body weight P  001 gonad weight P ≤ 005 triiodothyronine T3 level P ≤ 005 and mRNA expression P  001 At L1 locus newly created CpG site in GG genotype was highly methylated 933  while there was no difference of methylation level in the other two CpG sites among three genotypes AA genotype and AG genotype having higher T3 level were significantly different P ≤ 005 from GG genotype There were significant differences among body weights of AA AG and GG genotypes P  001 Gonad weights of AA genotype and AG genotype were significantly lower than GG genotype The GHR1 mRNA expression of GG genotype was significantly lower than AA and AG genotypes P  001 These implied that mutations and methylation status of GHR1 gene might influence the hormone level growth traits and gene expression in male halfsmooth tongue sole and the L1 locus could be regarded as a potential candidate genetic and epigenetic marker in halfsmooth tongue sole selection

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