西湖水域外来生物福寿螺的种类鉴定及种群遗传多样性研究

SPECIES IDENTIFICATION AND POPULATION GENETIC DIVERSITY OF NON-NATIVE APPLE SNAILS (AMPULLARIIDEA: POMACEA) IN THE WEST LAKE

  • 摘要: 为了解杭州西湖景区外来生物福寿螺的分布现状和群体遗传变异特征, 研究详细调研了西湖景区福寿螺的分布现状, 并针对连续六年采集的福寿螺样本开展了分子鉴定及种群遗传多样性研究。调查结果表明, 西湖福寿螺集中发生在苏堤以西, 其中西北部的西里湖、茅家埠、杭州花圃及岳湖水域的发生密度高, 在西南部的乌龟潭、浴鹄湾等水域发生密度较低。在602 bp长的线粒体COⅠ序列中, 共检测到79个变异位点, 生成了6个单倍型。序列相似性和系统发育关系分析表明, 西湖水域中Hap1-Hap5为小管福寿螺, Hap6为斑点福寿螺; 单倍型多样性、核苷酸多样性和核苷酸平均差异数分析表明, 不同年份的小管福寿螺单倍型多样性Hd为0.229—0.600, 核苷酸多样性π为0.011—0.027, 核苷酸平均差异数k为6.797—16.000, 两种福寿螺均有较低的种群遗传多样性, 显著性分析表明2018—2020年与2015—2017年间的种群遗传多样性无显著性差异。此外, 结合核基因EF1α序列分析表明西湖水域的福寿螺种群包括CC型(23.08%)、CM型(23.08%)和CB型(53.84%), 杂种所占比例高达76.92%以上, 群体广泛发生了种间杂交渐渗。由于引配水工程的连通性, 西湖水域的福寿螺向周边水系扩散风险较大, 研究为西湖景区福寿螺的防控提出了建议。

     

    Abstract: The exotic apple snails are big freshwater snails that have spread and damaged the West Lake for nearly 10 years. To understand the species and population genetic diversity of apple snails, we explored the distribution of the apple snails in the West Lake. Based on the samples collected in the past six years, identified the species, and analyzed their population genetic diversity. The results showed that the distribution of apple snails was concentrated in west of the Su Causeway, with a high density in the northwest area including Xilihu, Maojiabu, Hangzhou Flowerbed, and Yuehu, and low density in the southwest aera such as Wuguitan and Yuhuwan. We detected 79 variable sites, and defined 6 haplotypes based on mitochondrial COⅠ sequences. Sequences similarity and phylogenetic relationships analysis revealed that the Hap1-Hap5 were Pomacea canaliculata and the Hap6 was P. maculata in the West Lake. The analysis of haplotype diversity, nucleotide diversity, and average number of nucleotide difference indicated that the haplotype diversity (Hd) of P. canaliculata was 0.229—0.600, the nucleotide diversity (π) was 0.011—0.027, the average number of nucleotide difference (k) was 6.797—16.000, and both P. canaliculata and P. maculata in the West Lake have low genetic diversity. There was no significant difference in genetic diversity between 2018—2020 and 2015—2017. In addition, nuclear EF1α sequence analysis demonstrated that the apple snail populations of P. canaliculata in the West Lake included CC (23.08%), CM (23.08%), and CB (53.84%) types. Introgressive hybridization were widely observed in the apple snail populations in the West Lake with a rate over 76.92%. Due to the connectivity of the water diversion project, there is a risk of apple snails spreading to the surrounding wetlands in the West Lake. This study provides some suggestions for the establishment of effective prevention and control strategies of apple snails in the West Lake.

     

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