Abstract: SNP of growth hormone (GH) gene Intron4 of Tibetan chicken and recessive white chicken were detected by using modified allele specific PCR (M-ASP), PCR-RFLP and sequencing reaction and its associations with growth traits of Tibetan chicken was done. The results indicated that there were M-ASP and SacI-RFLP polymorphisms in Intron4 of GH gene and there was a C/G mutation by DNA sequencing and resulted in 3 genotypes CC, CG and GG. The distributions of three genotypes and two alleles between two chicken breeds were very similar and the frequencies of genotype CC and allele C were highest among them. The results χ2 showed that there were not significant differences in the frequencies of genotypes or alleles between the two chicken breeds (P＞0.05), however, there were significant differences within each of the two chicken breeds (P＜0.05), respectively. The results of analysis of variance showed that genotypes had significant effect on twelve growth traits of Tibetan chicken at 0.05 or 0.01 levels, and there was a positive relationship between genotype CC and body weight of Tibetan chicken at the age of 7 weeks (P＜0.05). It implies that GH gene is the major gene affecting growth traits of Tibetan chicken or it links with the major gene, and the mutation could be used as the molecular genetic marker to select Tibetan chicken for high body weight at the age of 7 weeks.

Key words: Tibetan chicken and recessive white chicken, SNP, M-ASP, Intron4 of GH gene, Growth traits, Association analysis