绵羊HBB基因和MC5R基因的变异与遗传效应研究

发布时间：2018-04-03 09:04

本文选题：HBB　切入点：MC5R　出处：《华中农业大学》2017年硕士论文

【摘要】：本研究探讨了绵羊HBB基因和MC5R基因的变异及其遗传效应。以不同地域的6个蒙系绵羊群体(湖羊、小尾寒羊、广灵大尾羊、滩羊、苏尼特羊和乌珠穆沁羊)和3个藏系绵羊群体(山谷型藏羊、欧拉型藏羊和高原型藏羊)为研究对象,利用DNA混合池法检测HBB基因和MC5R基因的SNP位点。采用直接测序法进行基因分型,分析HBB基因SNP位点等位基因频率和单倍型频率与海拔高度间的关系、MC5R基因SNP位点等位基因频率和单倍型频率与环境温度间的关系以及这两个基因SNP位点基因型和单倍型对湖羊产羔数的遗传效应。同时,从GenBank公共数据库收集了30个物种的HBB基因和36个物种MC5R基因的CDS序列,分析不同物种间相同基因的相似性、系统发生关系和选择方向;检测基因SNP位点在绵羊不同群体间的选择压力。旨在为深入研究HBB基因和MC5R基因的功能奠定基础,也为利用HBB基因和MC5R基因的分子标记进行绵羊产羔数的选育提供理论依据。研究结果如下:1.HBB基因共检测到22个SNP位点,其中8个SNP位点为非同义替换位点,即g.1087AT、g.1088AC、g.1111CG、g.1136AG、g.1162AG、g.1164GA、g.1165AC和g.1247TA位点。MC5R基因共检测到16个SNP位点,其中6个SNP位点为非同义替换位点,分别是g.625CT、g.1947GA、g.2028TA、g.2292GA、g.2451GA和g.2478GA位点。2.种间选择性检验表明HBB基因和MC5R基因均受到强烈的正选择作用。HBB基因编码的氨基酸序列中显著受到正选择的位点有9个(5A、9A、12T、50S、52D、69D、87Q、116R、125V);MC5R基因编码的氨基酸序列中显著受到正选择的位点有8个(31L、32H、42E、45L、47G、51R、83G、341T)。3.种内群体间的选择性检验结果表明HBB基因g.1164GA位点受到平衡选择的作用,该变异可引起氨基酸序列中蛋氨酸替换为缬氨酸;MC5R基因g.2028TA位点受到强烈的正选择作用,该变异可引起氨基酸序列中异亮氨酸替换为天冬酰胺。4.分析HBB基因22个SNP位点的等位基因频率和单倍型频率与9个绵羊群体生存环境海拔间的关系,发现g.1136AG位点的等位基因频率与海拔高度显著相关(P0.05),而位点g.787CT、g.800GA、g.809CG、g.889GA、g.956CT、g.957AG、g.958GA、g.968TC、g.1007TA、g.1020TA、g.1021CT、g.1087AT、g.1088AC、g.1111CG、g.1162AG、g.1165AC、g.1173CT和g.1176TC这18个位点的等位基因频率与海拔高度极显著相关(P0.01)。在这些与海拔相关的位点中,g.1087AT、g.1088AC、g.1111CG、g.1136AG、g.1162AG和g.1165AC位点为非同义替换位点。此外,HBB基因有2种单倍型即H1和H3的频率与海拔高度显著相关(P0.05)。5.分析MC5R基因16个SNP位点的等位基因频率和单倍型频率与蒙系绵羊6个群体生存环境的年平均温度间的关系,结果表明MC5R基因的16个SNP位点的等位基因频率和单倍型频率与年平均温度之间没有显著的相关性(P0.05)。6.对湖羊群体HBB基因和MC5R基因的SNP位点的基因型、单倍型与产羔数进行关联分析,结果表明HBB基因g.1164GA位点的基因型对第3胎产羔数有显著的遗传效应(P0.05),其中GG基因型个体的产羔数比GA基因型和AA基因型分别高出0.53头和0.49头;HBB基因SNP位点的单倍型对第3胎产羔数有显著的遗传效应(P0.05)。MC5R基因g.2393AG位点的基因型对第3胎产羔数有显著的遗传效应(P0.05),AA基因型个体的产羔数比AG基因型高出0.72头,而单倍型对产羔数的遗传效应不显著(P0.05)。综上所述,HBB基因在绵羊中受到平衡选择作用,MC5R基因在蒙系绵羊中受到正选择作用。HBB基因中与海拔显著相关的6个非同义替换位点与绵羊适应高海拔低氧环境有关。湖羊HBB基因g.1164GA位点和MC5R基因g.2393AG位点的变异与湖羊多羔性状有关。
[Abstract]:This study explores the variation and genetic effects of sheep HBB gene and MC5R gene. In 6 Mongolian sheep population in different regions (sheep, small tail Han sheep, Guangling sheep, Tan sheep, Sunite sheep and ujumqin sheep) and 3 Tibetan sheep populations (valley type Tibetan sheep and Tibetan sheep plateau type of Tibetan sheep) as the research object, SNP loci HBB and MC5R gene by DNA method. The mixed pool were genotyped by direct sequencing and analysis of the relationship between HBB gene SNP allele frequencies and haplotype frequency and elevation, the genetic effect of the relationship between MC5R gene SNP allele frequency and haplotype frequency and environmental temperature as well as between the two gene SNP genotype and haplotype on Hu littersize. At the same time, collected from the public database of GenBank HBB gene of 30 species and 36 species of MC5R CDS gene sequence analysis The similarity among species of the same gene, phylogenetic relationships and selection of direction; detection of SNP gene loci in the selection pressure between different groups of sheep. In order to lay a foundation for further research on HBB gene and MC5R gene function, but also provide a theoretical basis for breeding for fecundity of sheep by using molecular marker HBB gene and MC5R gene. The results are as follows: 1.HBB gene were detected in 22 SNP loci, 8 SNP loci were non synonymous substitutions, namely g.1087AT, g.1088AC, g.1111CG, g.1136AG, g.1162AG, g.1164GA, g.1165AC and g.1247TA loci of.MC5R gene of 16 SNP loci were detected, including 6 SNP loci for non synonymous substitutions, are g.625CT, g.1947GA, g.2028TA, g.2292GA, g.2451GA and g.2478GA loci.2. interspecific selective test showed that HBB gene and MC5R gene were subjected to positive selection effect of.HBB gene encoding the amino acid sequence of the strong Was subject to positive selection 9 loci (5A, 9A, 12T, 50S, 52D, 69D, 87Q, 116R, 125V); the amino acid sequence of MC5R gene encoding significantly under positive selection 8 loci (31L, 32H, 42E, 45L, 47G, 51R, 83G, 341T) results selection of.3. test among populations within species showed that the HBB gene g.1164GA locus by balancing selection. This mutation can cause methionine amino acid sequence replaced by valine; MC5R g.2028TA gene is under positive selection of strong, can cause the variation of amino acid sequence to replace the relationship between isoleucine asparagine.4. analysis of 22 SNP loci of HBB gene the allele frequencies and haplotype frequencies of 9 sheep populations in the living environment of the elevation, found that the g.1136AG allele frequency was significantly correlated with altitude (P0.05), and g.800GA, g.809CG, g.787CT loci, g.889GA, g.956CT, g.957AG, g.958GA, g.968TC, g.1007 TA, g.1020TA, g.1021CT, g.1087AT, g.1088AC, g.1111CG, g.1162AG, g.1165AC, g.1173CT and g.1176TC of the 18 allele frequency was significantly correlated with altitude (P0.01). In these sites related with altitude, g.1087AT, g.1088AC, g.1111CG, g.1136AG, g.1162AG and g.1165AC loci for non synonymous substitutions. In addition, there are 2 kinds of haplotype frequency and elevation of H1 and H3 was highly related to the HBB gene (P0.05).5. analysis of the relationship between the annual average temperature of 16 SNP loci of MC5R gene allele and haplotype frequencies of Mongolian sheep and 6 populations living environment. The results show that 16 SNP loci of MC5R gene the allele frequencies and haplotype frequencies are not significantly correlated with mean annual temperature (P0.05) type.6. gene SNP locus in Hu sheep population HBB gene and MC5R gene, haplotype association analysis and litter size, node The results show that the HBB genotype of g.1164GA gene had significant genetic effect on litter size (third P0.05), the litter size of GG genotype than GA and AA genotypes were higher than 0.53 and 0.49; HBB SNP gene haplotypes had significant genetic effect on litter size third (P0.05).MC5R genotype of g.2393AG gene had significant genetic effect on litter size (third P0.05), litter size of AA genotype AG genotype was 0.72 higher than the head, but there was no significant genetic effect of haplotypes on litter size (P0.05). In conclusion, the HBB gene by balancing selection in sheep in the MC5R gene is under positive selection in the.HBB gene significantly correlated with elevation of 6 non synonymous substitutions and sheep to adapt to high altitude hypoxia environment in Mongolian sheep. Sheep HBB gene g.1164GA mutation site and MC5R gene g.2393AG sites Related to sheep lamb traits.

【学位授予单位】：华中农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S826

【参考文献】