【作者】 齐国强；

【导师】 昝林森； 张桂香；

【作者基本信息】 西北农林科技大学 ， 动物遗传育种与繁殖， 2007， 硕士

【摘要】 本研究采用单链构象多态性(SSCP)方法并结合测序技术对10个中国地方水牛品种(贵州青水牛、涪陵水牛、江汉水牛、恩施山地水牛、西林水牛、陕南水牛、海子水牛、温州水牛、东流水牛、峡江水牛)150头个体线粒体DNA D-loop序列基因(约930bp)的多态性进行研究,结果表明:我国地方水牛品种在线粒体DNA D-loop区第一高变区(HV1)的变异率较高。通过SSCP方法显示出6种单倍型,据此确定了110个测序个体。测序结果共发现了50种单倍型,107个多态位点(简约多态位点73个,单一多态位点34个),约占核苷酸序列的11.50%,其单倍型多样度(haplotype diversity, Hd)为0.8952±0.0240,核苷酸多样度(nucleotide diversity,π)为0.0200±0.0056,平均核苷酸差异(average number of nucleotide differences, k)为18.4450,在不同品种之间,差异极显著,其中江苏海子水牛的单倍型多样度、核苷酸多样度和平均核苷酸差异是最高的,其次为贵州青水牛,温州水牛和江汉水牛,其他品种则较低。在这50种单倍型中,43种为各品种特有的单倍型,7种为品种间共享的单倍型。最大的共享单倍型H1包含除江苏海子水牛之外9个品种的33个个体,单倍型H26、H41和H43均包含5个以上个体,单倍型H2、H6、H22、H24、H27、H34、H48均包含2个或2个以上个体,其余单倍型均只有一个个体。中国地方水牛的单倍型数目在每个品种中分布不同,最小为5,最大为9;其单倍型多样度和核苷酸多样度分别为0.8332-1.0000和0.0096-0.0327,这些都表明中国水牛具有丰富的遗传多样性。以GenBanK上公布的江河型印度摩拉水牛D-loop序列(AF197215)为外群,用MEGA3.1和Network 4.2.0.1软件对中国地方水牛50种mtDNA单倍型进行亲缘关系和系统进化分析,构建的NJ系统树表明中国水牛都属于沼泽型水牛,并且包含了2个母系起源,分别命名为A支系和B支系,以此确定了区分两个支系的基本变异位点。其中A支系包含了所有研究品种中的36个单倍型的78个个体,分别占到了总数的72%和70.9%,居主导地位。B支系虽然在分布上不如A支系广泛,但是在单倍型和核苷酸的多样度上要比A支系丰富。除峡江水牛只有A支系外,其他9个中国地方水牛品种在A支系和B支系中均有分布,表明了mtDNA的起源与各品种之间的地理分布没有必然联系。对所选的10个品种从整体上进行核苷酸mismatch分布发现:这些品种没有经过群体扩张;但是对分别处于支系A和支系B聚类分支的个体进行mismatch分布发现:支系A的母系来源经过群体扩张,支系B没有经过群体扩张。更多还原

【Abstract】 The single strand conformation polymorphism combined with DNA sequencing of control region was used to study the genetic polymorphism of 150 mitochondrial DNA in 10 buffalo breeds. The result showed:The 10 buffalo breeds had high variation in the HV1 of D-loop sequence. 6 haplotypes were indicated in D-loop region by SSCP, and so 110 individuals were sequenced. The results showed that 107 polymorphism sites which were about 11.5% of the all detected sites in the 110 sequences, that of 73 sites were parsim-imformative sites and 34 sites were singleton sites. Its haplotypes diversity was 0.8952±0.0240, nucleotide diversity was 0.0200±0.0056, the average number of nucleotide difference was 18.4450. There was significant difference in breeds, in which Jiangsu Haizi water buffalo’s haplotype diversity, nucleotide diverse and the number of average nucleotide differences was highest, Guizhou black water buffalo, the Wenzhou water buffalo and the Jianghan water buffalo was higher, then others were low.43 kinds various varieties unique single time and 7 kinds single time which share for the variety in the 50 kinds of haplotypes.The biggest sharing haplotype H1 contained 33 individuals of 9 variety except the Jiangsu Haizi water buffalo, haplotypes of H26, H41 and H43 contained more than 5 individuals, haplotypes of H2、H6、H22、H24、H27、H34 and H48 contained 2 or more than 2 individuals, others only contained an individual. The haplotype numbers of Chinese water buffalo’s were different in each breed, the smallest number was 5 and the biggest number was 9; The haplotypes diversity and nucleotide diversity respectively were 0.8332-1.0000 and 0.0096-0.0327. Chinese water buffalo’s average haplotypes diversity and the nucleotide diversity distinction were 0.8952±0.0240 and 0.0200±0.0056, indicated that Chinese water buffalo had rich heredity multiplicity.Take India murrah river water buffalo D-loop sequence (the GenBanK number as AF197215) as the outside group and analysing the relation and system evolvement of 50 kinds of mtDNA haplotypes of Chinese water buffalo, as well as constructing the NJ genealogical tree which showed that Chinese water buffalo was morass water buffalo, and contained 2 lineages, lineage A and lineage B. Lineage A contained 78 individuals of 36 haplotypes, separately accounted for 72% and 70.9%. Although lineage B was not widespread than lineage A in the distribution, lineage B was richer than lineage A in haplotypes and nucleotide diversity. Besides Xiajiang water buffalo, other 9 breeds of Chinese water buffalo had both lineage A and lineage B, indicated that the origin of mtDNA does not have the positive connection with geographic distribution of different buffalo.By distributing the nucleotide mismatch of ten breeds, we discovered that there was no colony expand in breeds, maternal origin of lineage A had colony expand and it was no colony expand about lineage B.更多还原