| Tibetan cashmere goat have strong adaptability to the environment of low oxygen,high cold and strong ultraviolet radiation in Tibet Plateau.The cashmere quality is excellent,It is a precious cashmere goat variety resources in Tibet and event in China.But its cashmere yield is not high due to natural and human factors,The current production of cashmere in Tibetan cashmere goat unable to meet the demand of the international and domestic markets.Thus,how to improve the quantity of cashmere production in Tibetan cashmere goat is an urgent problem to be solved.Studies showed that Hoxc13,KAP9.2,TGF-?I and TGF-?RI gene play a vital role in the growth of wool.However,the related genes have not been reported in high elevation areas of Tibetan cashmere goat.Therefore,Ear edge skin tissue were collected from 200 Tibetan cashmere goats in six counties(Rutog,Coqen,Baingoin,Gê'gya,Gêrzê and Gar).We have obtained the Hoxc13,KAP9.2,TGF-?I and TGF-?RI gene CDS from Tibetan cashmere goat by cloning and sequencing;analyzed genetic variation of the four genes in Tibetan cashmere goat by direct sequencing method;and analyzed the expression level of the the Hoxc13,KAP9.2,TGF-?I and TGF-?RI gene at different altitudes in Tibetan cashmere goat by qRT-PCR.The results obtained were as follows:1.Hoxc13 gene CDS sequence contains 993 bp,accession number is MF151165.KAP9.2 gene CDS sequence contains 576 bp,accession number is MF320738.TGF-?I gene CDS sequence contains 1173 bp,accession number is MF173604.TGF-?RI gene CDS sequence has two subtypes,the shorter one was 1497 bp in length,and the longer one is 1509 bp in length,accession number are MF186222 and MF351607 respectively.2.3 new SNPs on exon 1 of Hoxc13 gene were detected,which are c.70G>T,c.120C>A and c.258C>G locus,respectively.and c.70G>T locus is missense mutation which results in amino acid change from alanine to threonine,and the other 2 loci were synonymous mutations.25 SNPs and a 30 bp-deletion mutation in exon of KAP9.2 gene were identified,c.76C>A,c.151A>C,c.273G>A,c.279C>A,c.302C>G,c.574C>T,c.584G>A site were the new SNP,of the 25 SNPs,12 sites were missense mutations.They were c.59C>G,c.65T>C,c.76C>A,c.151A>C,c.153C>A,c.238G>A,c.302C>G,c.320G>C,c.388C>T,c.515G>C,c.388C>T,respectively.and the other 13 sites were synonymous mutations.2 new mutation sites on exon 1 of TGF-?I gene were identified,which are c.138C>T and c.228C>G locus,respectively.and the 2 sites were synonymous mutations.1 new mutation on exon 5 of TGF-?RI gene was identified,the c.825T>C locus was a synonymous mutation.3.The mRNA expression level of KAP9.2 in high altitude area was significantly higher than that in extra high altitude area.the expression level of TGF-?I and TGF-?RI in high altitude area were significantly lower than that in extra high altitude area,while Hoxc13 mRNA expression level had no difference at different altitudes.Undoubtedly,the results from present study not only help to reveal the polymorphism of Hoxc13,KAP9.2,TGF-?I and TGF-?RI gene in Tibetan cashmere goat and its relative expression in different altitudes,and also provide the basic data for the main gene research and selection of the cashmere yield. |
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