福寿螺线粒体DNA COⅠ基因序列测定及分类地位

Sequencing Cytochrome Oxidase Subunit Ⅰ of Mitochondrial DNA and the Taxonomic Status of Apple Snails

对国内6个地区共29个福寿螺(Apple Snails)个体mtDNA COⅠ基因进行了扩增和序列分析,并结合GenBank中报道的福寿螺6个种Pomacea canaliculata、P.insularum、P.diffusa、P.haustrum、P.paludosa、P.camena和Pila属P.conica的同源序列,对国内入侵福寿螺的分类地位与分子系统发育进行了分析。结果表明,扩增的mtDNA COⅠ基因序列长度为619bp,序列间未见插入和缺失,其中核苷酸多态位点99个,简约信息位点80个;碱基A、T、C、G平均含量分别为23.6%、39.1%、16.6%和20.7%,A+T的含量(62.7%)明显高于C+G的含量(37.3%);6个地区的福寿螺共有13种单倍型,广州、钦州和吉安分别有3种单倍型,茂名、厦门和成都分别有2种单倍型,而广州、厦门和钦州3个地区之间共享一种单倍型。进一步的分子遗传距离分析表明,这6个地区福寿螺个体与P.diffusa、P.haustrum、P.paludosa和P.camena的遗传距离为0.114～0.191,而与P.insularum和P.canaliculata的同源性较高,其中单倍型1、2、3、7、8、10、11、12与P.canaliculata的遗传距离为0～0.074,单倍型4、5、6、9、13与P.insularum的遗传距离为0.011～0.063。构建的分子系统树显示7个分支,分别为Pomacea属6个种和Pila属P.conica,其中单倍型1、2、3、7、8、10、11、12与Pomacea canaliculata聚成一支,单倍型4、5、6、9、13与P.insularum聚成一支。序列同源性、遗传距离和系统进化树分析结果表明,国内入侵福寿螺有P.canaliculata和P.insularum两个种,而且这两个种在入侵扩散过程中已相互混杂。本研究为今后开展福寿螺的资源调查、控制和管理等提供科学依据。

The fragments of mitochondrial cytochrome oxidase subunit I （CO I ） gene were amplified from 29 Apple Snails in 6 different locations,then sequenced and analyzed. Compared with the corresponding CO I gene sequences of Pomacea canaliculata , P. insularum , P. diffusa , P. haustrum , P. paludosa , P. camena and Pila conica in the ampullariids published in GenBank,the taxonomic status of introduced Apple Snails in six regions of China was examined. The results showed that the length of CO I gene sequence was 619 bp,including 99 variable sites and 80 parsimony sites. The average contents of A,T,C and G were 23.6% ,39.1% ,16.6% and 20.7% , respectively. Total 13 different haplotypes of apple snails were found in 6 different locations. There were 3 haplotypes in Guangzhou, Qinzhou and Jian, and two haplotypes in Maoming,Xiamen and Yaan. In addition,3 locations of Guangzhou, Xiamen and Qinzhou all existed a uniform haplotype. Molecular analyses showed that the genetic distances ranged from 0. 114 to 0. 191 between apple snails in six locations in China and Pomacea diffusa,P, haustrum,P, paludosa, P. camena, 0. 011 to 0.063 between P. insularum and Haplotype 4,5,6,9, 13,and 0 to 0. 074 between P. canaliculata and other eight haplotypes. Phylogenetic analysis based on the mitochondrial CO I gene segregated them into seven major clades including 6 species of the genus Pomacea and one of the genus Pila. Haplotype 1,2,3,7,8,10, 11,12 and Pomacea canaliculata formed a clade that was sister to the P. insularum clade including Haplotype 4,5,6,9,13. Sequence analysis, genetic distances and Phylogenetic trees suggested that there were two species of non-native apple snails in China continent including P. canaliculata and P. insularum, and this two species had mixed with each other in the course of pervasion. This study will provide a scientific basis for developing resources investigation,control and management of apple snails in the future.