【作者】 杨晓军；

【导师】 赵有璋；

【作者基本信息】 甘肃农业大学 ， 动物遗传育种与繁殖， 2001， 博士

【摘要】 应用RAPD技术对甘肃省和青海省分布的藏系绵羊中8个具有代表性的群体进行了研究，建立了适宜于藏系绵羊RAPD分析的最佳反应条件，并用现代群体遗传学方法评估了藏系绵羊遗传多样性和群体间的遗传关系，探讨了藏系绵羊的品种（系）的起源和分化。 藏系绵羊随机扩增多态性DNA（RAPD）在PE2400型DNA扩增仪上的最佳反应条件是：在25μL的反应体系中，模板DNA的量为60～120ng，引物量为4～8pmol，Mg²⁺浓度为2.0mM，Taq DNA聚合酶为1～2.5U，dNTP浓度为150～200μM；94℃预变性3min后40次循环的参数设定为：94℃ 1min，36℃ 1min，72℃ 2min又30sec，最后72℃延伸10min。利用这些条件对藏系绵羊进行RAPD分析，其结果的重复性和可靠性大大提高。 使用18种随机引物在48个个体中共检测到4447条RAPD标记片段，标记多态频率平均为88.17％，品种间的平均遗传多样性指数（Ho值）为0.37，总群体的遗传多样性指数（Hsp值）为1.51；核基因组DNA的遗传多样性在品种内和品种间的分布分别为24.5％和75.5％；藏系绵羊品种内个体间的平均遗传距离指数（D值）为0.177，变异范围为0.152～0.197，品种群间的平均D值变异范围为0.419～0.569，总平均值为0.492，品种（系）间的遗传变异远远大于品种（系）内的遗传变异。 研究结果表明，藏系绵羊在核DNA方面存在一定的遗传变异，具有较为丰富的品种间遗传多样性，而品种内的遗传多样性则相对较为贫乏；现有藏系绵羊类群已具有明显的品种间遗传分化；宕昌黑藏羊是藏系绵羊中一个独立的品种；藏系绵羊可以划分为高原草地型（AMT）和山谷型（VGT）两大类群或类型；RAPD技术是研究家养动物遗传多样性、群体遗传结构和品种（系）分化的有效方法。更多还原

【Abstract】 The molecular techniques of random amplified polymorphic DNA (RAPD) were used to investigate the genetic diversity of eight breeds of Tibet sheep from Gansu and Qinghai province of northwest China. The genetic diversity and relationships and differentiation of these breeds were evaluated and discussed with several analysis methods of modern population genetics. In 25iiL reaction systems, 60?--l2Ong DNA templates, 4～ 8pmol primers, 2. 0mM Mg2+ ,1～2. 5U Ta DNA polymerase and 150～ 200 M dNTPs were the optimization conditions of RAPD reaction of Tibet sheep in GeneAmp PCR System 2400. The parameter of 40 cycles after 3mm pre-denaturalization were that:940C 1mm, 36 0C 1mm, 72CC 2. 5mm, 720C 10mm. As above, the results of RAPD reaction could be repeated and the reliability of one would be lifted increasingly. 4447 fragments of RAPD were detected within 48 animals with 18 arbitrary oligonucleotide primers, and the percentage of polymorphic fragments was 88. 17%. The average genetic diversity index (Ho) within breeds was 0.37. The average diversity over all populations (Hsp) was 1. 51. Portioning of genetic variability on average showed that, 24. 5% distributed within and 75. 5% between breeds. The average genetic distance index (D) was 0. 177(0. 152?. 197) within and 0.492(0.419 0.569) between breeds of Tibet sheep. The genetic variation between breeds was bigger than within one. The results showed that the genetic diversity between breeds was remarkably abundance in nuclear DNA, and relatively scarce within breeds of Tibet sheep. The differentiation of breeds had exited in Tibet sheep. The breeds of Tibet sheep could be divided into Altiplano Meadow Type (AMT) and Valley Grassplot Type (VGT). Tangehang black Tibet sheep is a new breed. At last, RAPD analysis was effective method of the studies on genetic diversity, genetic construction, origin and genetic ? differentiation of domestic animals.更多还原