Study On Associations Of SNP Of Three Cytochrome P450Enzymes Gene And The Reproductive Endocrine Of Japanese Flounder (Paralichthys Olivaceus)

As the most important species for sea water cultivating, Japanese flounder(Paralichthys olivaceus) has important economic value。This paper first studied thesingle nucleotide polymorphisms (SNPs)of CYP17-Ⅰgenne、CYP17-Ⅱgene and thepromoter region of CYP19A, and then analysised the effect of these SNPs to thereproductive endocrine of cultured Japanese flounder. The aim of this study is toprovide some valuable information for the marker assisted breeding and reproductiveregulation of Japanese flounder. The main results and conclusions are as follows:1. Detection and analysis the SNPs of CYP17-Ⅰgene of Japanese flounderIn this study, single-stranded conformational polymorphism (SSCP) techniquewas used to characterize polymorphisms of the coding region of CYP17-Ⅰ gene inJapanese flounder. Two Single nucleotide polymorphisms (SNPs) were detectedwithin the CYP17-Ⅰ gene of Japanese flounder. They were SNP1(c.C445T) locatedin exon2and SNP2[c.T980C (p.Phe307Leu)] located in exon5. Multiplecomparisons revealed that CT genotype of SNP1had a much lower serumtestosterone (T) level than CC genotype (p<0.05) while GSI of individuals with CCgenotype of SNP2was higher than those with TT genotype (p<0.05). Four diplotypeswere constructed based on the two SNPs and the diplotype D3had a significiantly lowserum testosterone (T) level and GSI.2. Detection and analysis the SNPs of CYP17-Ⅱgene of Japanese flounderThree SNPs were identified in CYP17-Ⅱ gene of Japanese flounder. They werec.G594A (p.Gly188Arg), c.G939A and c.G1502A (p.Gly490Asp). SNP1which waslocated in exon4of CYP17-Ⅱ gene was significantly associated with GSI.Individuals with GG genotype of SNP1had significantly lower GSI (p<0.05) thanthose with AA genotype or AG genotype. SNP2was located at the CpG island of CYP17-Ⅱ gene and led to the AA genotype lose a CpG island. Individuals with AAgenotype of SNP2had significantly lower serum testosterone (T) level and higher HSIcompared to those of individuals with GG genotype. However, the SNP3(c.G1502A)located in exon9was not detected to have association with the four measuredreproductive traits. During the six diplotypes, diplotype D5had the highest serumtestosterone (T) level while diplotype D1had the lowest one. Diplotype D6had thelowest GSI than other diplotypes.3. Detection and analysis the SNPs of5’ promoter region of CYP19A gene ofJapanese flounderThree blocks including42SNPs were identified in the promoter region ofCYP19A gene of Japanese flounder. P1block had4linkaged SNPs, which wereA-2200G、C-2180T、A-2126G、A-1997G. P2block was consisted of11SNPs,which were T-1927insertion or deletion, C-1899insertion or deletion, T-1772C、C-1766T、TGTCAAC-1752~-1744insertion or deletion. P3block was consisted of27SNPs which were linkaged. They were A-1257T、AAAAAT-1252~-1245insertion ordeletion, A-1216G、AATGAAATTTA-1213~-1203insertion or deletion, T-1202C、TAA-1093~-1091C、A-1014G、T-1001C、C-987T、A-980C. Multiple comparisonsrevealed that P1and P2black were associated with serum E2level in femaleindividuals and GSI in male individuals (p<0.05). And P3black had significantlyassociations with GSI in female individuals (p<0.05) and serum testosterone (T) leveland HSI in male individuals (p<0.05). All the three blocks had significantlyassociation with the reproductive endocrine of Japanese flounder.In a word, three genes which were CYP17-I, CYP17-Ⅱand CYP19A were choseusing functional candidate genes method in this study. The three genes played animportant role in the synthesis of sex hormones. The polymorphisms in the codingregion of the three genes were detected and analyzed the association of the SNPs withreproductive traits of Japanese flounder. These results indicated that SNPs of the threegenes were significantly associated with reproductive traits of Japanese flounder andcan be used in the molecular marker assisted breeding of Japanese flounder.