Studies On Genetic Diversity Of Thiamine Related Candidate Gene And Its Correlation With Thiamine Contents In Chicken Muscle

Thiamine(vb1) is one of the key components for meat flavor. And the process of synthesis and metabolism for thiamine is very complicated. TPK(Thiamine pyrophosphokinase) is important for the formation of a coenzyme required for central metabolic functions. In the first part of this study, change of muscle thiamine contents in Wenchang chickens form 4 to 12 weeks and differences of muscle thiamine contents in different genealogys in Rugao chickens at the age of 12 weeks were studied. In the second part, TPK1 gene was studied as a candidate gene for thiamine contents in chicken. To explore the relationships between TPK1 gene with thiamine contents in chicken,single strand conformation polymorphism (SSCP) and gene sequencing were performed to screen single nucleotide polymorphism ( SNP ) in four Chinese indigenous chicken breeds, Rugao chickens(RG), Taihe Silkies(TS), Xiaoshan chickens(XS), Baier chickens(BE), and an exotic breed, Recessive White broilers(RW). The main results were as follows1. In the same condition of management, Increasing, the thiamine contents of muscle were decreasing continuously in Wenchang chickens from 4 to 12 weeks of age. Significant differences of thiamine content were found among genealogys at the age of 12 weeks in the Rugao chicken. The relationship between body weight and muscle's thiamine contents in breast was significantly negative(P < 0.05,r is -0.200); which confirms the fact that genetic may play a key role on thiamine content of chicken. And this may settle a foundation for researching the mechanism of flavor in Chinese indigenous breeds in the molecular level and be of significance for four breeding practice chicken breeds of chickens.2. All 7 exons with flanking intronic sequences and 3′-region of TPK1 gene were analyzed by the method of PCR-SSCP analysis, combined with gene sequencing in the five chicken breeds mentioned above. We found 2 SNPs in total, one SNP were detected in 3′- UTR and the sequencing results indicated that BB genotypes had only one base difference with AA genotype( C2132T ), while CC genotype had only one base difference with BB genotype( C2132A ); another SNP was found in exon 7 with a A809G . These two polymorphic sites were nominated as TPK1A, TPK1B respectively. TPK1B were detected only in the Rugao chicken. The genotypes distribution among different chicken breeds is significantly difference, and genotypes distribution among different chicken genealogys is also significantly different. Only the TPK1A locus show a significant relationship with thiamine content in breast muscle. Across the breeds,thiamine content of individuals with AA genotype was significantly higher than that of with AB and BB genotype (P < 0.01). Result indicated that this locus may be a candidate assistant marker for selection thiamine contents.