玉树马和德保矮马SLC36A1基因多态性研究

摘要

控制马香槟毛色的CH (Champagne gene)基因家族包含4个候选基因(SLC36A1、SLC36A2、SLC36A3、SPARC),研究发现SLC36A1基因外显子2的突变是造成马香槟毛色的关键位点.为揭示中国马SLC36A1基因遗传多态性,本研究以玉树马和德保矮马共74个样本为研究对象,以马DNA池为模板扩增SLC36A1基因的10个外显子及部分内含子序列并进行测序分析.共发现马SLC36A1基因5个SNPs,分别位于内含子3(g.26699953 A＞G,g.26699851G＞C,g.26699850 G＞C),外显子4(g.26699562 G＞A)及外显子6(g.26697018 C＞T).利用PCR-RFLP方法对74个家马样本进行基因分型,发现外显子6的SNP有基因型CC、CT;外显子4的SNP有基因型GG、GA;内含子3的g.26699850 G＞C突变有基因型GG、GC;内含子3的另外2个SNPs(g.26699953 A＞G,g.26699851 G＞C)通过测序,发现有AA、AG、GG与GG、GC、CC基因型.所有5个马SNPs均为野生型占主要优势.由此界定了马SLC36A1基因有9种单倍型(H1-H9),其中H5是最主要的单倍型.德保矮马遗传多样度为0.4190,比玉树马(0.2228)高,表明德保矮马香槟毛色遗传多态性比玉树马更丰富.玉树马与德保矮马的平均单倍型多样度为0.3160,表明其香槟毛色遗传多态性相对较低.%The champagne coat color in horses is controlled by a single autosomal-dominant champagne gene (CH),which contains four candidate genes (SLC36A1,SLC36A2,SLC36A3,SPARC),of which a mutation in exon 2 of SLC36A1 gene has been linked to horse champagne coat color.To reveal the genetic diversity of SLC36A1 gene in Chinese domestic horses,ten exons and partial introns sequences of 74 samples including Yushu horse and Debao pony breed were sequenced using DNA pool as template.Five SNPs including intron 3 (g.26699953 A＞G,g.26699851 G＞C,g.26699850 G＞C),exon 4(g.26699562 G＞A) and exon 6 (g.26697018 C＞T)were detected in two horse breeds.PCR-RFLP was used to genotype the five SNPs in 74 samples of Yushu horses and Debao pony breed,showing CC and CT genotypes in exon 6,GG and GA genotypes in exon 4,GG and GC genotypes in exon 3 of g.26699850 G＞C.The remaining 2 SNPs (g.26699953 A＞G,g.26699851 G＞C)showed AA、AG、GG and GG、GC、CC genotypes respectively using sequencing genotyping.The 5 SNPs indicated that the wild genotypes are the dominant genotypes.Nine haplotypes (H1-H9) were determined based on the genotype and H5 was the dominant haplotype.The haplotype diversity (H=0.4190) of Debao pony was richer than that of Yushu horse (0.2228),indicating the genetic diversity of Debao pony is more abundant.The average haplotype diversity is 0.3160showing the two horse breeds have low genetic diversity in champagne coat color.