Population genetic structure of the land snail Camaena cicatricosa (Stylommatophora, Camaenidae) in China inferred from mitochondrial genes and ITS2 sequences

Abstract

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.

Genetic analysis of Cryptozona siamensis (Stylommatophora, Ariophantidae) populations in Thailand using the mitochondrial 16S rRNA and COI sequences

“…In addition, the climate may effect on the population size. This could be observed in other snails such as Camaena cicatricosa and Succinea caduca [ 28 , 29 ]. In addition, the genetic diversity of the Collisella subrugosa snail in Brazil showed variation due to environmental conditions and differing selection pressures [ 47 ].…”

“…The 58 COI sequences were classified into 14 haplotypes, 9 that were unique and 5 that were shared between the different populations. High haplotype diversity (39 mitochondrial haplotypes) was also reported from Camaena cicatricose in China [ 29 ]. In contrast, low haplotype diversity (2 COI haplotypes) was found in A .…”

“…siamensis population may be affected by the ecological environment, climate barriers, and geographic barrier factors [ 2 , 29 ]. This was supported by previous studies that showed that the ecological environment factor on population differentiation, has been reported in other land snails, such as Camaena cicatricose [ 29 ] and Cyclophorus fulguratus [ 42 , 51 ]. In addition, the migration and expansion repeated of population from different areas lead to continuously mix the populations of land snails.…”

“…fulica , could be spread through shipments of plants especially pot plants [ 55 ], as well as the C . cicatricosa in China could be spread through cargo transportation [ 29 ]. Therefore, the dispersal of C .…”

“…In China, Zhou et al studied population genetic structure of the land snail Camaena cicatricosa from 20 locations using mitochondrial gene (COI and 16S rRNA) and internal transcribed spacer (ITS2) sequences. This showed significant fixation indices of genetic differentiation and high gene flow among most populations [ 29 ]. In Thailand, the genetic variation of the COI in Achatina fulica was found to be low [ 30 ].…”