Polymorphisms And MRNA Expression Levels Of IGF-1,FGF5 And KAP1.4 In Tibetan Cashmere Goat(Capra Hircus)

Tibetan cashmere goat,a domestic goat breed in China,are famous for cashmere’s length,color,glossiness and tension strengths.Because of the low cashmere production in Tibetan cashmere goat,the essential problem which should be solved is that how to improve the cashmere production.Investigation of other goat and sheep breeds suggested that Insulin growth-like factor I(IGF-1),Fibroblast growth factor 5(FGF5)and Keratin Associated Protein 1.4(KAP1.4)could be potentially implicated in cashmere growth(hair growth).But little studies about the association between these three genes and cashmere production in Tibetan cashmere goat had been carried out.Therefore,240 Tibetan cashmere goat from seven counties(Rutog,Coqen,Nyima,Baingoin,Ge’gya,Gerze and Gar)of Ngari(78°23’～86°11’E,29°40’～35°42’N)and Nagqu Prefecture(84°55’～95°5’E,29°55’～36°30’N)were chosen and ear tissue samples were collected from living body.The aim of this study was to investigate whether the polymorphisms and mRNA expression levels of IGF-1,FGF5 and KAP1.4 were associated with the cashmere production in Tibetan cashmere goat.The results of present study are summarized as following:1.Compared with Tibetan cashmere goat and other goat and sheep breeds,sequences identity of the fragments of IGF-1,FGF5 and KAP1.4 were 98.36%,99.87%and 99.84%respectively.Tibetan cashmere goat,Capra hircus and Ovis aries shared homology and the phylogenetic tree also showed a long genetic distance of Tibetan cashmere goat,Homo sapiens and Mus musculus.2.According to the sequences analysis of 204 samples,no SNP were found in IGF-1 and FGF5 while two new SNP loci were found in KAP1.4.Both of these two new SNP loci were C-T mutation(g.209C>T and g.245C>T)and only g.245C>T lead to amino change(Proline-Leucine).Calculation of gene frequencies and allele frequencies of these two SNP loci implied that the mutation rate of Tibetan cashmere goat was the highest in Coqen county.3.mRNA expression levels of FGF5 and KAP1.4 in Tibetan cashmere goat from different counties was significantly different(p<0.05).mRNA expression levels of FGF5 in Gerze was significantly higher than that in Rutog(p<0.05).mRNA expression levels of KAP1.4 in Coqen and Nyima was significantly higher than that in other five counties(p<0.05).4.mRNA expression levels of IGF-1,FGF5 and KAP1.4 in Tibetan cashmere goat with different ages and sex was similar(p>0.05).But there was a tendency that mRNA expression levels of IGF-1 and KAP1.4 was up-regulated with the age increasing.Conclusion:Results of this study indicated that Tibetan cashmere goat and other goat and sheep breeds shared high similarity and they were homologous.Two new SNP loci were detected in Tibetan cashmere goat and the mutation of these two SNPs could increase the cashmere production.mRNA expression levels of FGF5 and KAP1.4 were related with cashmere production in Tibetan cashmere goat.Therefore,FGF5 and KAP1.4 may act as candidate genes of cashmere growth in Tibetan cashmere goat for further investigation.