【作者】 霍俊宏；

【导师】 韩俊文； 马月辉； 周忠孝；

【作者基本信息】 山西农业大学 ， 动物遗传育种与繁殖， 2005， 硕士

【摘要】 本研究旨在分析中国6个地方绵羊品种mtDNA的遗传多样性,分别从新疆和静县的巴音布鲁克区、昆仑山北麓策勒县、库车县、克孜勒苏柯尔克孜自治州和叶城地区这五个地方采集到巴音布鲁克羊（BY）、策勒黑羊（CL）、卡拉库尔羊（KL）、柯尔克孜羊（KE）和叶城羊（YC）五个地方品种,又从青海省采集到青海黑藏羊（QH）一个地方品种,共计283个地方绵羊品种的样品,基于PCR-SSCP和克隆测序技术,利用自行设计的6对引物（OV4、OV5、Or6、OV7、OV8、OV9）和参照Hiendleder等（1998a）的D-Loop区引物（OV1）以及郭军（2004）的两对引物（OV2、OV3）共9对引物对以上中国6个地方绵羊品种的mtDNA做了系统的分析研究,探讨了群体内和群体间的遗传变异,目的是为地方绵羊遗传资源的合理利用及保护提供科学的依据。研究结果如下: 1.对DNA序列多重比对之后,得出A、B、C三种单倍型在D-loop区内的碱基替换共有62处变异,而且全部为碱基转换（没有一处是颠换的）。 2.通过PCR-SSCP试验和D-loop区序列的聚类结果表明:上述绵羊品种中确实存在着C这种单倍型,也就是说它们共有三个母系起源,这将有助于绵羊起源中心的确定。 3.上述绵羊C单倍型在Cytb和ND2上存在着2个非同义突变:Asn¹⁴⁶³⁴→Ser¹⁴⁶³⁴和Met⁴²⁰⁸→Thr⁴²⁰⁸。此外,在Cytb、ND2和ND4片段中还存在着7个同义突变位点。 4.上述绵羊mtDNA D-Loop区中存在着明显的长度变异,引起变异原因主要是由于1个或几个碱基或串联重复基元序列的插入（或缺失）造成的,不存在绵羊品种特异性。 5.本试验发现:在所研究的中国6个地方绵羊品种线粒体的16343位与16344位之间（即:在D-Loop区的907与908位之间）插入一个碱基“C”,而在绵羊mtDNA的全序列中（指GenBank上已经发表的）没有这个碱基。 6.本试验研究的绵羊在各个不同片段中所扩增出的A、B、C三种单倍型基本一致,但不是完全连锁,存在着微小的差异。 7.从NJ法与UPGMA法构建了系统进化树和用最大似然法构建的D-loop树中可明显的看出中国6个地方绵羊品种三种单倍型的分布情况;用NJ法构建的三种单倍型树可以判断出巴音布鲁克羊和卡拉库尔羊之间的遗传关系最近。更多还原

【Abstract】 The genetic diversity of 283 sheep of six indigenous sheep breeds in China was analyzed using mtDNA marker based on the requirement of project assignment. The sheep breeds include Bayinbuluke sheep with short and fat tail from Bayinbuluke district of Hejing county, Cele Black sheep with short and thin tail from Cele county in North Kunlun Mountain, Kalakuer sheep with fat rump from Kule county.Keerkezi sheep with short and fat tail from Kezilesukeerke Prefecture and Yecheng sheep with short and fat tail from Yecheng Prefecture of Xinjiang, and Qinghai Black Tibetan sheep with long and fat tail from Qinghai province in China. The study was based on PCR-SSCP and subsequent clone sequencing protocols. Six pairs of primers for the PCR-SSCP of sheep mtDNA were designed by author （OV4, OV5, OV6, OV7, OV8 and OV9） and other primer pairs to amplify the D-Loop region designed byHiendleder （1998a） and Gunjun （OV2 and OV3） were also used in this study. The main The thesis objective of this study was to address the genetic variation within population and between populations which could provide baseline information for conservation and utilization of the indegenous sheep genetic resources. The results were as following:1. Comparison of the mtDNA sequences showed the replacement substitutions of base pairs in D-Loop between the hyplotypes A, B and C. AH the substitutions are transitions alone.2. PCR-SSCP and dendrograms of D-Loop proved that the hyplotype C also existin othersheep breeds of China.3. Two nonsymonymous mutations were found in ND2 and Cytb as of Asn¹⁴⁶³⁴ —? Ser¹⁴⁶³⁴ and Met⁴²⁰⁸—?Thr⁴²⁰⁸.Apart from these, 7 symonymous mutations were found in all sheep mtDNA sequences.4. Length variation in insertion or deletion of base pair or tandemly repeated sequence in D-Loop was found in six sheep breeds.5. An insertion of a base pair （c） in the six sheep breeds （between 16343 and 16344） was detected compared to the published sheep mtDNA complete sequence in the GenBank.6. Hyplotypes A, B and C were basically in the same linkage in six sheepsheep breeds with a few exceptions.7. Phylogenetic trees of NJ, UPGM and amaximum likelihood estimation support the classification of three hyplotypes in six sheep breeds in China and Bayinbuluke sheep and Kalakuer sheep had a closer relationship compared to others.更多还原