基于cpDNA rps16序列分析兰考泡桐与白花泡桐和毛泡桐的遗传关系

摘要

[Objective]To explore the change of chloroplast genetic characteristics and laws of Paulownia elongata, P.fortunei and P.tomentosa and to discuss the genetic relationship among the three species.[Method]The genetic differences of the Chloroplast DNA rps16 region sequences of P.elongata,P.fortunei and P.tomentosa were ana-lyzed by using sequencing method.The DNAs were extracted from each 15 individuals of P.elongata,P.fortunei and P.tomentosa,then were amplified with PCR to obtain specific fragment which were purified and sequenced. Quick sort were completed by the software Clustal X 2.0,multiple sequence were aligned by using software MEGA 4,and then the characteristics and the K2P genetic distance of the alignment sequence were also calculated.[Re-sult](1).The sequence lengths of rps16 region from P.elongata were measured by 916 933 bp;those from P. fortunei was calculated by 932 bp;and those from P.tomentosa were 916 918 bp after aligned.The length of rps16 sequence was 938 bp after aligned by the software Clustal X 2.0,and the average GC content was 34.31%. The amount of total variable loci detected from the aligned sequences was 10,accounting for 1 .07% of the entire length of the sequence.The amount of variable loci (insertion-deletion site)was 9,accounting for 90%of the total variable loci,for 0.96%of the entire sequence.The amount of variable loci (substitution site)was 1 ,accounting for 10% of the total variable loci,for 0.11 % of the entire sequence.(2).Total 10 variable loci were detected from the aligned sequences,of which 9 (90%)sites were same between P.elongata and P.fortunei,while there was no same base between P.elongata and P.tomentosa.[Conclusion]According to the analysis on sequence characteristics and mutation sites of rps16 sequences from the three species of Genus Paulownia,in chloroplast ge-netic aspects,the results illustrated that there were much more similar plastid inheritances between P.elongata and P.fortunei than between P.elongata and P.tomentosa;indicating closer relationships between P.elongata and P. fortunei.From the above,P.elongata and P.fortunei could be inferred from the same maternal lineage.%【目的】通过测序法分析兰考泡桐与白花泡桐和毛泡桐在叶绿体rps16序列上的遗传差异，旨在分析三者之间在叶绿体基因上的变化特点和规律，探讨其种间的遗传关系。【方法】选取兰考泡桐、白花泡桐和毛泡桐各15个样本，对其提取的DNA用PCR扩增获得特异片段，并将其纯化与测序。利用软件Clustal X 2．0对所得序列进行排序；运行MEGA 4软件，进行多序列比对，分析其序列特征，并计算出K2P遗传距离。【结果】（1）对获得的rps16序列进行测定分析，得兰考泡桐序列长度分别为932933 bp；白花泡桐序列长度为932 bp；毛泡桐序列长度分别为916918 bp。对所得rps16序列进行排序后的长度为938 bp，平均GC含量为34．31％。3个种所代表的个体之间共有10个变异位点，占整个序列长度的1．07％。其中有9个变异位点属于碱基插入或缺失类型，占变异位点总数的90％，占整个序列长度的0．96％。有1个变异位点属于碱基替换类型，占整个变异位点总数的10％，占整个序列长度的0．11％。（2）整个rps16片段的序列共有10个变异位点，其中兰考泡桐与白花泡桐在总的变异位点上，具有一致的碱基位点9个，占总变异的90％。而兰考泡桐与毛泡桐相比，没有相同的碱基。【结论】根据三种泡桐的rps16序列的序列特征和变异位点的分析，表明在叶绿体遗传方面，兰考泡桐具有与白花泡桐更多相似的遗传物质，其亲缘关系较近。综上所述，推测兰考泡桐与白花泡桐可能来自同一母系遗传。