Key Laboratory of Molluscan Quarantine and Identification of AQSIQ, Fujian Entry-Exit Inspection & Quarantine Bureau, Fuzhou, Fujian, 350001, China.
National Wetland Museum of China, Hangzhou, Zhejiang, 310013, China.
Sci Rep. 2017 Nov 15;7(1):15590. doi: 10.1038/s41598-017-15758-y.
The phylogeographic structure of the land snail Camaena cicatricosa was analyzed in this study based on mitochondrial gene (COI and 16srRNA, mt DNA) and internal transcribed spacer (ITS2) sequences in 347 individuals. This snail is the vector of the zoonotic food-borne parasite Angiostrongylus cantonensis and one of the main harmful snails distributed exclusively in China. The results revealed significant fixation indices of genetic differentiation and high gene flow between most populations except several populations. An isolation-by-distance test showed no significant correlation between genetic distance and geographical distance among C. cicatricosa populations, which suggested that gene flow was not restricted by distance. The levels of haplotype and nucleotide diversity of C. cicatricosa were generally high, except those in some special populations, according to the mt DNA and ITS2 data. Furthermore, the phylogenetic trees and asteroid networks of haplotypes indicated nonobvious genetic structure, the same as results got based on the synonymous and non synonymous sites of 347 sequences of the COI gene. All lines of evidence indicated that climatic changes and geographical and human barriers do not substantially affect the current population structure and distribution of the investigated snails.
本研究基于线粒体基因（COI 和 16srRNA，mtDNA）和内部转录间隔区（ITS2）序列，对 347 个个体的地蜗牛 Camaena cicatricosa 的系统地理结构进行了分析。这种蜗牛是动物源性食源性寄生虫广州管圆线虫的载体，也是中国特有的主要有害蜗牛之一。结果显示，除了几个种群外，大多数种群之间的遗传分化固定指数和基因流都很高。隔离距离检验表明，C. cicatricosa 种群之间的遗传距离与地理距离之间没有显著相关性，这表明基因流不受距离限制。根据 mtDNA 和 ITS2 数据，除了一些特殊种群外，C. cicatricosa 的单倍型和核苷酸多样性水平普遍较高。此外，单倍型的系统发育树和小行星网络表明遗传结构不明显，这与基于 COI 基因的 347 个序列的同义和非同义位点得到的结果相同。所有证据表明，气候变化以及地理和人为障碍对调查蜗牛的当前种群结构和分布没有显著影响。
