楔形前殖吸虫核糖体全序列的特征分析

Characterization of Complete Nuclear Ribosomal DNA Sequences of Prosthogonimus cuneatus

楔形前殖吸虫(Prosthogonimus cuneatus)是禽类和鸟类输卵管、法氏囊和直肠常见的寄生虫之一,对禽和鸟类危害较大。利用PCR对楔形前殖吸虫核糖体全序列进行了扩增,并探讨了其与其他吸虫的进化关系。结果发现,楔形前殖吸虫核糖体全序列长10713 bp,其中18S、ITS1、5.8S、ITS2、28S、IGS的长度分别为1970、1271、161、224、4155、2932 bp;核糖体全序列有15对正向重复序列和34对反向重复序列,正向重复序列全部位于ITS1和IGS区域;基于18S基因的进化分析显示,楔形前殖吸虫与同属的卵圆前殖吸虫及同科的稀有裂睾吸虫聚在同一分支上,与同目的Brachycladiidae和Auridistomidae两科吸虫亲缘关系较其他科近。首次解析了楔形前殖吸虫的核糖体全序列特征,并探讨了其与其他吸虫的进化关系,研究结果为前殖科吸虫的分类学、群体遗传学和系统学研究提供了新资料。

Prosthogonimus cuneatus is one of the most common fluke that parasitizes in the oviduct,bursa and cloaca and affects the health of poultry and birds.In the present study,the complete nuclear ribosomal DNA sequences of P.cuneatus was amplified by polymerase chain reaction(PCR)and the phylogenetic relationship with other trematodes was also reconstructed.The results showed that the length of complete nuclear ribosomal DNA sequence of P.cuneatus was 10713 bp,and the length of 18S,ITS1,5.8S,ITS2,28S and IGS complete sequences were 1970 bp,1271 bp,161 bp,224 bp,4155bp and 2932 bp,respectively.Fifteen pairs of forward repeat sequences and 34 inverted repeat sequences were found in the complete sequences of ribosomal DNA,which all forward repeat sequences were located in ITS1 and IGS sequence regions.Phylogenetic analysis based on the 18S rDNA indicated that P.cuneatus clusters together with the same genus P.ovatus and the same family Schistogonimus rarus,and they are more closer to families Brachycladiidae and Auridistomidae than others of the same order.This is the first time the complete ribosomal DNA of P.cuneatus was sequenced and analyzed,and its evolutionary relationship with other trematodes is also discussed,which will provide important basic information on the taxonomy,population genetics and systematics of Prosthogonimidae.