【作者】 马玉花；

【导师】 杨吉安； 贾万忠；

【作者基本信息】 西北农林科技大学 ， 野生动植物保护与利用， 2004， 硕士

【摘要】 运用克隆测序法测定了15个来自不同地区杜仲的ITS区全序列，通过序列分析探讨不同地区杜仲的遗传变异。结果表明：杜仲不同品系的ITS区序列长度为587bp -589bp，长度变异不大（仅相差2bp），其中ITS-1区为218bp-219bp，ITS-2区为205bp-206bp，5.8S rDNA为164bp；ITS-1区G+C含量的变化范围为63.93%- 65.74%，ITS-2区为65.69%-66.67%，ITS区(包括ITS-1，5.8S rDNA和ITS-2)为62.76%- 63.42%；不同样品ITS-1和ITS-2的变异位点共23个（5.41%），信息位点7个（1.65%），且变异位点稳定；5.8S rDNA在杜仲不同品系间的长度高度保守，且无变异位点。虽然杜仲样品的ITS区序列信息位点不是很高，但其序列分析资料为杜仲种的鉴别及该科的分类方面提供了新的手段，所得的ITS区序列为杜仲的分子标记的确定提供了依据，说明核糖体DNA ITS区序列用于杜仲的分子鉴定是可行的。运用DNASTAR软件进行系统发育分析表明，杜仲15个样品间的同源性均在96.9%以上，差异性均在0.0-0.7%间；系统发生树上所有样品间的最大遗传距离为0.4，说明不同分布区的杜仲间的变异只是种内变异的一种形式，同时也再次说明ITS序列不仅适用于较高分类等级的系统学研究，也能反应种内变异及多态性。杜仲不同样品基于ITS序列的聚类结果与它们按叶型分类的结果不一致；另外，来自同一地区的样品并不一定处于同一分组，而来自不同地区的样品也可能属于同一分组。因而认为杜仲的遗传变异只有进一步与其它方面的证据和特征相结合，进行深入的研究，才能最终确定它们的合理的系统发育关系。另外,我们还测定了杜仲18S区部分序列,序列长度为1609bp,与GenBank中的杜仲18S序列存在差异。更多还原

【Abstract】 The sequence of the ITS region (including ITS-1, 5.8S rDNA and ITS-2) of nuclear ribosomal DNA of 15 species of Eucommia ulmoides Oliv. from different geographical region of China were determined. The results show that the size of the ITS region of Eucommia ulmoides Oliv. is from 587bp to 589bp (ITS-1 is from 218bp to 219bp, 5.8S rDNA is 164bp ，and ITS-2 is from 205bp to 206bp), and the aligned length of ITS region is 589 position which provides 5.41% variable sites and 1.65% phylogenetical informative sites when gaps are treated as missing，the variable sites are very stable, therefore ITS sequences would be suitable marker for the construction of Eucommia ulmoides Oliv. phylogeny. The length of 5.8S rDNA is very conservative in these species and there have no variable site. The content of G+C of ITS-1 region is from 63.93% to 65.74%，ITS-2 region is from 65.69% to 66.67%，and ITS region (including ITS-1,5.8S rDNA and ITS-2) is from 62.76% to 63.42%. On the basis of phylogenetic analysis of nucleotide sequences,the DNA sequence homologyes of Eucommia ulmoides Oliv. from different geographical region is above 96.9%,and the divergence is from 0.0 to 0.7%. Phylogram tree based on ITS sequence data indicates that the samples from same region is not always clustered, and the samples from different regions may be in same section；on the other hand，it is not corresponding to the result that determined by the shape of leaf. Therefore, the rational phylogenetic relationship can be determined through associated these ITS data with other evidence.On the other hand we determined the 18S region of nuclear ribosomal DNA of Eucommia ulmoides Oliv.. The length of 18S region is 1609bp，and it have some distinction with the sequence of Eucommia ulmoides Oliv. from GenBank.更多还原