Polymorphism Of KIF Ⅰ Gene Associated With Cashmere Traits In Three Cashmere Goat Breeds

The experiments was conducted to detect polymorphisms of the goat keratin intermediate-filaments type I (KIF I) gene in three Chinese cashmere goat breeds.Total of 220 Xinjiang goats, 305 Nanjiang cashmere goats and 280 Bogeda Cashmere goats were used in this study. PCR-RFLP,PCR-SSCP and DNA sequencing were used to detect polymorphisms of the goat keratin intermediate-filaments type I (KIF I) gene in three Chinese cashmere goat breeds. At the same time analyzed its associations on cashmere fineness, cashmere thickness, cashmere yield and body weight after combed in Xinjiang cashmere goats.The results as follows:1. The results of PCR-RFLP and DNA sequencing showed: there is a novel C to T mutation in exon1 720bp, The mution caused C changed to R, this is a missense mutation; there is a a novel A to C mutation in intron1 1020bp, which forms a HaeIII endonuclease restriction site. Three unique PCR-RFLP banding patterns (genotypes AA, AC and CC) were found, A allele is advantage allele,the frequencies of the A allele in Xinjiang cashmere goats and Nanjiang,cashmere goats, Bogeda Cashmere goats were 0.700,0.729 and 0.747, respectively.In KIF type I exon3, there is a C to T mution in 3212bp, which reduces a HaeIII endonuclease restriction site, Three unique PCR-RFLP banding patterns (genotypes AA, AC and CC) were found. A allele is advantage allele,the frequencies of the A allele in Xinjiang cashmere goats and Nanjiang, cashmere goats, Bogeda Cashmere goats were 0.823,0.777 and 0.883, respectively. The motion not caused amino acid change, this is a Synonymous mutation.2. The results of PCR-RFLP and DNA sequencing showed: KIF I exon2 has no polymorphism.There were 2 SNP in exon4, the mution C to T in 4563bp was a missense mutation, which caused T changed to M.. The mution A to G in 4699bp was a synonymous mutation, which not caused amino acid change. 3.From the data analysized we know: In three KIFI polymorphism site, heterozygosity in Xinjiang cashmere goat are largest, so the Xinjiang cashmere goat has greatest choice potential.In KIFI-P1 enzyme locus,All breeds showed moderate polymorphism, tests of Hardy-Weinberg equilibrium confirmed that all three breeds were in equilibrium; In KIFI-P3 locus, Xinjiang cashmere goat showed moderate polymorphism, but showed low polymorphism, and Nanjiang cashmere goat was not in Hardy-Weinberg equilibrium; In KIFI-P4 locus, All breeds showed moderate polymorphism in two mutation site, and the genotypic distributions in three cashmere goat breeds were not in Hardy-Weinberg equilibrium.4.The impact of KIFI gene polymorphism on cashmere traits (cashmere fineness, down cashmere thickness, cashmere yield, body weight after combing) in the Xinjiang goats breed were analyzed, the result indicated that: in KIFI-P1 enzyme locus greater cashmere fineness in genotype AA compared to genotype CC ( P < 0.05). Suggesting that this mutation may be a molecular markers that closely linked to a master gene or regulatory factor which impacting cashmere fineness.Therefore,used KIF type I gene genetic marker-assisted selection cashmere fineness has certain basis.