绵羊脂肪型脂肪酸结合蛋白基因（A-FABP）变异研究

发布时间：2018-04-19 19:53

本文选题：A-FABP基因 + 绵羊　；参考：《甘肃农业大学》2015年硕士论文

【摘要】：脂肪型脂肪酸结合蛋白(adipocyte fatty-acid binding protein,A-FABP)属于脂肪酸结合蛋白(fatty-acid binding protein family,FABPs)家族,主要功能为结合和转运长链脂肪酸参与脂肪酸代谢过程。本研究基于Ensemble数据库中绵羊A-FABP基因全序列,对7个绵羊品种共20个样本的A-FABP基因全序列测序分析,以明确绵羊A-FABP基因的变异和单倍型特征。结果表明:PCR扩增获得绵羊A-FABP基因全长6474bp,A、T、G、C 4种碱基的平均百分比分别为31.48%、33.02%、17.21%和18.29%,A+T平均含量为64.50%,G+C平均含量为35.50%。共发现48处单碱基变异位点和2处微卫星位点M1((TG)n)和M2((TA)n),单一变异位点、2核苷酸变异位点和3核苷酸变异位点比例分别为28.85%、40.4%和0.02%。共发现转换、颠换、插入和缺失4种变异类型,其占变异位点总数的比例分别为45.83%、31.25%、2.08%及20.83%。共发现19种单倍型,单倍型多样度为0.995。A-FABP基因19个单倍型序列的NJ树分化为2个聚类簇,表明A-FABP基因单倍型最初由2个主要单倍型衍化形成。运用PCR-SSCP方法检测了4个绵羊品种的A-FABP基因外显子2-内含子2和外显子3-内含子3区域的遗传多态性并对其变异特性进行了系统分析。结果显示,4个绵羊品种的外显子2-内含子2区域共检测出4个等位基因(A、B、C、D),表现为6种基因型(AA、AC、AD、BB、BC、CC),A等位基因为优势等位基因,在4个群体中的频率均分别是0.4865、0.5333、0.7500和0.4592;不同群体的优势等位基因型不同,滩羊群体、藏绵羊群体、青海细毛羊群体中的优势等位基因型分别为BC、AA、AC。外现子3-内含子3区域在4个群体中共发现A、B、C、D 4个等位基因,表现为AA、BB、AB、AC和CD 4种基因型,等位基因A为优势等位基因。基因型和等位基因在群体间分布不均衡。只有外显子3-内含子3区域等位基因D在61bp处发生的A→G的突变造成了氨基酸突变。其它突变均发生在内含子区域,所以未发生氨基酸的突变。外显子2-内含子2和外现子3-内含子3区域共有8个突变位点,其中1个位点为碱基缺失,占突变位点的12.5%;6个位点发生转换,占突变位点的75%;1个位点发生颠换,占突变位点的12.5%。在外显子2-内含子2区域,除藏绵羊为中度多态(0.25㩳PIC㩳0.5)外,甘肃高山细毛羊、滩羊、青海细毛羊(PIC㧐0.5)均属于高度多态。在外显子3-内含子3区域除甘肃高山细毛羊为高度多态外(PIC㧐0.5),其它三个绵羊群体均属于中度多态(0.25㩳PIC㩳0.5)。χ2检验结果显示,4个绵羊群体在外显子2-内含子2和外显子3-内含子3区域杂交类群中均偏离了Hardy-Weinberg平衡状态(P㩳0.05)。综上所述,绵羊A-FABP基因是高度多态的,遗传多样性十分丰富,对其多态性的研究可以促进绵羊A-FABP基因的进化研究,同时,为绵羊生长和脂肪性状候选基因的研究积累素材。
[Abstract]:Adipocyte fatty-acid binding protein (A-FABPs) belongs to the fatty acid binding protein binding protein familyFABPsfamily. The main function is to bind and transport long chain fatty acids to participate in fatty acid metabolism. Based on the complete sequence of sheep A-FABP gene in Ensemble database, 20 samples of 7 sheep breeds were sequenced and analyzed to identify the variation and haplotype characteristics of sheep A-FABP gene. The results showed that the average percentages of the four bases of sheep A-FABP gene were 31.48 ~ 33.02%, 17.21% and 18.29% respectively. The average percentage of total length of A-FABP gene was 64.50% and the average percentage of G C was 35.50%. A total of 48 single base mutation sites and 2 microsatellite sites were identified. The percentages of single mutation site and 3 nucleotide variation site were 28.85% and 0.02%, respectively. Four types of variation were found: conversion, transversion, insertion and deletion, and the proportion of them to the total number of mutation sites was 45.83% and 20.83%, respectively. A total of 19 haplotypes were found, and the haplotypes with 19 haplotypes of 0.995.A-FABP gene differentiated into 2 clusters, indicating that the haplotypes of A-FABP gene were originally derived from two major haplotypes. The genetic polymorphisms of exon 2-intron 2 and exon 3-intron 3 of A-FABP gene in four sheep breeds were detected by PCR-SSCP method and their variation characteristics were systematically analyzed. The results showed that a total of 4 alleles were detected in exon 2-intron 2 region of four sheep breeds, which showed that 6 genotypes (AA-AA-AA-AA-AC-BCCC-CG-A) were the dominant alleles, and 4 alleles were detected in the exon 2-intron 2 region of four sheep breeds, which were the dominant alleles. The frequencies of the four populations were 0.4865 and 0.4592.The dominant alleles of different populations were different, the dominant alleles of Tan sheep, Tibetan sheep and Qinghai fine wool sheep were BCU AAAC. Four alleles were found in the exon 3-intron 3 region in four populations. The allele A was the dominant allele in ABAC and CD4 genotypes. Genotypes and alleles were unevenly distributed among populations. Only the allele D of exon 3- intron 3 occurred at 61bp, resulting in amino acid mutation. Other mutations occurred in the intron region, so there was no amino acid mutation. There are 8 mutation sites in the region of exon 2-intron 2 and exon 3-intron 3, among which one locus is base deletion, accounting for 12.5% of the mutation site, six loci are converted, accounting for 75% of the mutant sites, and one locus is transverted, accounting for 12.5% of the mutation sites. In the region of exon 2-intron 2, Gansu alpine fine wool sheep, Tan sheep, Qinghai fine wool sheep and Qinghai fine wool sheep were highly polymorphic except Tibetan sheep (0.25 PIC-0.5). In the region of exon 3- intron 3, except Gansu alpine fine wool sheep with high polymorphism, the other three sheep populations all belong to the middle polymorphic polymorphic polymorphic PIC3. 蠂 2 test showed that four sheep populations contained exon 2-intron 2 and exon 3- intron 3 in both exon 2 and exon 3- exon 3. The results of 蠂 2 test showed that four sheep populations had high polymorphism in exon 2- intron 2 and exon 3- exon 3. The cross group of sub-3 region all deviated from the Hardy-Weinberg equilibrium state. In conclusion, sheep A-FABP gene is highly polymorphic and rich in genetic diversity. The study of its polymorphism can promote the evolutionary study of sheep A-FABP gene, and accumulate materials for the study of candidate genes for growth and fat traits of sheep.
【学位授予单位】：甘肃农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S826

【参考文献】