【作者】 骆爽；

【导师】 刘廼发；

【作者基本信息】 兰州大学 ， 动物学， 2009， 硕士

【摘要】 对采自西藏高原的80个红尾沙蜥和34个西藏沙蜥样本采用微卫星法进行多样性分析。7对引物在红尾沙蜥中共检测出44个等位基因,在西藏沙蜥中共检测出42个等位基因。所有位点都呈现多态性。红尾沙蜥每个位点的等位基因数在3-6个之间,平均每个位点的等位基因数为4.7个,平均观测杂合度和平均多态信息含量分别为0.3607和0.5953。西藏沙蜥每个位点的等位基因数在3-7个之间,平均每个位点的等位基因数为5.3个,平均观测杂合度和平均多态信息含量分别为0.3996和0.5561。两个物种的所有种群之间存在59.17%的遗传变异。红尾沙蜥种群存在38.13%的遗传变异,比西藏沙蜥的43.19%要低。计算结果发现,Rst与地理距离之间呈不显著正相关。红尾沙蜥和西藏沙蜥的观测杂合度,期望杂合度和Rst与海拔高度呈不显著负相关。红尾沙蜥与西藏沙蜥的分歧时间在4.43Mya左右。红尾沙蜥受到高原湖泊隔离作用的影响,经历了多次异域片断化隔离事件,导致各种群之间基因流受限。UPGMA聚类图中,尼玛种群较其他种群遗传距离远。尼玛地理位置偏西,存在的红尾沙蜥历史较长且比较原始。Arlequin分析显示,尼玛种群与其他种群的分歧时间在1.97±0.53Mya左右。在西藏沙蜥扩散的过程中,冈底斯山和唐古拉山之间地区的东方亚种受到地理隔离作用的影响,与西藏沙蜥指名亚种发生了分化。拉萨种群与仲巴种群的分化时间在3.4±0.42Mya左右,与萨嘎种群的分化时间在3.0±0.58Mya左右。UPGMA聚类显示三个种群仍属于同一分支。对采自苏干湖地区的9只青海沙蜥母本和27只子代,青藏高原地区的9只红尾沙蜥母本和23只子代,7只西藏沙蜥母本和27只子代,分成母本和子代两个群体采用微卫星法进行多样性分析。红尾沙蜥母本的平均杂合度和平均多态信息含量分别为0.3268和0.5973,子代的平均杂合度和平均多态信息含量分别为0.2039和0.5437;母本与子代两个群体之间遗传变异为14.9%。西藏母本的平均杂合度和平均多态信息含量分别为0.3188和0.5463,子代的平均杂合度和平均多态信息含量分别为0.2951和0.4348;母本与子代两个群体之间遗传变异为21.9%。青海沙蜥母本的平均杂合度和平均多态信息含量分别为0.4066和0.5515,子代的平均杂合度和平均多态信息含量分别为0.3663和0.5234;母本与子代两个群体之间遗传变异为9.78%。结论表明母本的遗传多样性普遍高于子代,母本与子代之间主要遗传变异发生物种的群体内部,即母本个体之间和子代个体之间的变异要大于母本与子代之间的变异。子代个数与母子间群体遗传差异成非显著负相关。对三种沙蜥的亲子鉴定表明,三个物种的家族中均出现了基因型上的差异。计算基因频率,发现红尾沙蜥的035,095家族,西藏沙蜥的193,188家族,青海沙蜥的SX35家族偏离了HWE。这些家族的子代基因型差异较多,遗传学父亲至少存在两个以上,外源父系的进入导致了基因频率的改变。其他出现基因型差异的家族,在基因频率的改变上也出现了偏离。表明至少有一个以上的遗传学父亲存在。红尾沙蜥070家族,西藏沙蜥127,192家族出现基因型差异的座位少,统计未显示基因频率的偏离,因此不能对其存在多重父权做出认定。更多还原

【Abstract】 To study rules of population genetics variance along altitude,we used seven microsatellite loci data to infer genetic structure in 80 individuals of Phrynocephalus erythrurus sampled from seven geographic locations and of 34 individuals of Phrynocephalus theobaldi from two geographic locations in the Tibetan Plateau.A total of 44 alleles at the 7 loci tested with an average of 4.7 alleles per locus were found in six P.erythrurus populations,the observed heterozygosity was 0.1456-0.4757,the averge PIC was 0.5953.In three P.theobaldi populations 42 alleles were tested out with an average of 5.3 alleles per locus,the observed heterozygosity was 0.1632-0.5119 with averge PIC of 0.5561.All loci of the samples were polymorphic.None of the sample populations showed significant departures from Hardy-Weinberg equilibrium.Between all populations,the variance was 59.17%.Rst and geographic distance was positive correlation with altitude.There were no significant negative correlation between Rst,Ho,He of the two species and altitude.At high elevation,both P.erythrurus and P.theobaldi had more low genetic diversity. Variation coefficient of temperature along altitude was a standard to scale whether environment was stable.The result showed P.erythrurus and P.theobaldi had more low genetic diversity at high elevation with unstable environment.This study suggested population genetic diversity showed a trend of decreasing with increased altitude,and populations lived in unstable environment had low genetic diversity.Differentiation between P.erythrurus and P.theobaldi was about 4.43 Mya.P. erythrurus populations were isolated by lakes of Tibetan plateau,the gene flow was restricted.UPGMA showed Nima population was far from others.Arlequin calculated differentiation of this population was about 1.97±0.53Mya.Mountains effected pervasion of P.theobaldi which induced subspecies differentiation.All spamples of P.erythrurus,P.theobaldi and Phrynocephalus vlangalii were were separated into female parent group and offspring group.We analyzed the genetic diversity parameter,variance between and within these two groups using seven microsatellite loci.The genetic diversity of female parent was higher than offspring generally.The variance between two groups of the three species was singly 14.9%, 21.9%and 9.87%.The number of offspring was non-significantly negatively correlated with genetic differences between female and offspring groups.Genotype and allele frequency based on microsatellite loci data were identified individuals which had different fathers.The results showed in five families at least more than two fathers were concerned with the offsprings.However offsprings of some families were not identified because of lacking enough data.更多还原