线粒体基因组揭示我国福寿螺的种群遗传结构及扩散路径

Objective:Pomacea spp.is one of the first invasive alien species in China.Since its invasion,it has been widely distributed in many places in southern China.There are as many as three invasive species in the wild,and there is a trend of spreading northward.This study aims to explore its main species with a northward distribution trend and possible invasion events.This study takes a global scale as the research scale and takes the main invasive apple snail populations in China as the research object.Through haplotype analysis,phylogenetic analysis and genetic diversity of the mitochondrial oxidative chromase I gene(COI),the genetic structure of Chinese apple snails was analyzed,and infer its invasion source and route. Methods:This study collected a total of 119 samples from 10 regions,and assembled the complete mitochondrial genome based on whole-genome sequencing data,successfully obtaining the complete mitochondrial sequences of 113 apple snail individuals.At the same time,this study collected 1,602 apple snail mitochondrial COI data in the NCBI database,and conducted phylogenetic,genetic structure and haplotype network analysis together with existing data. Results:(1)There are 1715 COI sequences with a sequence length of 523 bp,totaling 111 haplotypes,among which Hap107 is the unique haplotype discovered in this study.111 haplotypes were clustered based on sequence similarity,and finally all haplotypes were divided into 3 groups.The haplotype phylogenetic tree constructed based on ML and BI showed a consistent topology.The establishment of an unrooted tree for the 13 protein-coding genes of the samples collected in this study showed that the Pomacea canaliculata,the Pomacea maculata,and the Pamacea occulta are obviously clustered into three branches,and the Pomacea maculata and the Pamacea occulta have a closer genetic relationship,while the Pomacea canaliculata have regional differences..(2)Genetic diversity analysis showed that the genetic diversity of the Pomacea canaliculata population is the richest.The Pomacea maculata has higher nucleotide diversity and the Pamacea occulta has higher haplotype diversity.(3)The haplotype network diagram shows that the Pomacea canaliculata show a multi-center radial distribution;among the Pomacea maculata,Brazil has an obvious network distribution,and North America and Asia have begun to show a center-radial distribution(originating from South America,introduced to North America,spread to Asia);the Pamacea occulta is distributed in a single center and radial pattern.(4)The results of the neutrality test analysis showed that the Tajima's D value of the Pamacea occulta was-2.09681,P<0.05,and the Fu and Li's value was-7.394,indicating that there may be population expansion. Conclusions:It supplements the existing distribution data of golden apple snail and provides direct evidence of its distribution in the north;The genetic structure of three main species of apple snails currently distributed in China has been clarified;The possible diffusion paths between Pomacea canaliculata and Pomacea maculata and various countries were discussed;It was inferred that there may be recent population expansion of the cryptic apple snail,and a new haplotype distribution was found.