广西扇棘单睾吸虫5.8S rRNA序列及二级结构的研究

目的 比较分析广西人体扇棘单睾吸虫、扇棘单睾吸虫和钩棘单睾吸虫5.8S rRNA序列及二级结构,探讨他们的进化关系.方法 提取广西扇棘单睾吸虫DNA,PCR扩增并测定5.8S rDNA序列;登录GenBank获取扇棘单睾吸虫和钩棘单睾吸虫5.8S rDNA序列.应用相关软件将5.8S rDNA基因转换成5.8S rRNA.采用Zuker算法,构建5.8S rRNA分子二级结构;计算3种吸虫间的遗传距离和同源性,分析5.8S rRNA序列及其二级结构特征.结果 广西人体扇棘单睾吸虫与扇棘单睾吸虫5.8S rRNA分子序列比较显示第81、83、84、129和143位共5个碱基发生变异,这些突变碱基均位于5.8S rRNA分子二级结构未配对碱基区,未引起5.8S rRNA二级结构的明显变化;与钩棘单睾吸虫比较,显示第13、27、49、66、99、152、157位共7个碱基发生变异,其中3个碱基发生在配对区,4个替代发生在未配对区,碱基变异引起两种吸虫5.8S rRNA二级结构的明显不同;广西扇棘单睾吸虫与扇棘单睾吸虫和钩棘单睾吸虫的遗传距离分别为0.031和0.044,同源性分别为96.9%和95.6%.结论 广西人体扇棘单睾吸虫5.8S rRNA序列与扇棘单睾吸虫高度同源,二级结构无明显不同,与钩棘单睾吸虫同源性较低,二级结构明显不同.

Study on sequence and secondary structure of Haplorchis taichui from Guangxi

Objective To explore the evolution of Haplorehis taiehui from Guangxi, Haplorehis taiehui and Haplorchis pumilio by analyzing the sequence and secondary structure of 5.8S rRNA genes. Methods The genomie DNA of Haplorehis taiehui from Guangxi was extracted. The 5.8S rDNA was amplified by PCR and the PCR products were sequenced. The 5.8S rDNAs of Haplorehis taiehui and Haplorehis pumilio were obtained from Gene Bank.The 5.8S rDNAs of the above trematodes were all transformed into 5.8S rRNAs by software. Homogeneity and genetic distance matrix were analyzed by software. The secondary structures of the 5.8S rRNAs were constructed with Zuker method. Results Comparing with Haplorehis taiehui, the 5.8S rRNA sequences of Haplorehis taiehui from Guangxi showed 5 mutation sites located in the 81th, 83th, 84th, 129th and 143th nueleotide. Those mutation sites were located in unpaired regions. The secondary structural characters of the 5.8S rRNA did not show signifi- cantly chang. Comparing with Haplorehis pumilio, 5.8S rRNA of Haplorehis taiehui from Guangxi showed 7 mutation sites located in the 13th, 27th, 49th, 66th, 99th, 152th and 157th, 3 of them were located in paired regions and 4 in unpaired regions. Those mutations caused the secondary structures of 5.8S rRNA significant change between two trematodes. Genetic distances among Haplorehis taiehui from Guangxi, Haplorehis taiehui and Haplorehis pumilio were 0.031 and 0.44, respectively. And Homogeneity was 96.9% and 95.6%, respectively. Conclusions Haplorehis taiehui of Guangxi showed a high homogeneity with Haplorehis taiehui. And the secondary structure of 5.8S rRNAs did not show significantly changes. Haplorehis taiehui of Guangxi showed a low homogeneity with Haplorehis pumilio. And the secondary structure of 5.8S rRNAs showed significant changes.