First genetic assessment of brackish water polychaete Tylorrhynchus heterochaetus: mitochondrial CO/sequences reveal strong genetic differentiation and population expansion in samples collected from southeast China and north Vietnam  

作　　者：Xing-Han Chen Sen Yang Wei Yang Yuan-Yuan Si Rui-Wen Xu Bin Fan Le Wang Zi-Ning Meng 

机构地区：[1]Department of Food and Environmental Engineering,Key Laboratory for Marine Estuary Fishery Resources Protection of Yangjiang City,Yangjiang Polytechnic,Yangjiang,Guangdong 529500,China [2]College of Animal Science and Technology,Zhongkai University of Agriculture and Engineering,Guangzhou,Guangdong 520175,China [3]Temasek Life Sciences Laboratory,National University of Singapore,Singapore 117604,Singapore [4]State Key Laboratory of Biocontrol,Institute of Aquatic Economic Animals,and the Guangdong Province Key Laboratory for Aquatic Economic Animals,Life Science School,Sun Yet-Sen University,Guangzhou,Guangdong 510275,China [5]Southern Laboratory of Ocean Science and Engineering,Zhuhai,Guangdong 519000,China

出　　处：《Zoological Research》2020年第1期61-69,共9页动物学研究（英文）

基　　金：supported by the IndustryAcademic Research Cooperation Program of Academician Workstation of Guangdong Province(2013B090400017);Natural Science Foundation of Guangdong Province(2016A030307036);Yangfan Innovative&Entrepreneurial Research Team Project for Guangdong Province(201312H10)

摘　　要：Tylorrhynchus heterochaetus is a widespread benthic polychaete worm found in coastal brackish waters of the west Pacific.It has high ecological and economic value as a biomarker of water quality and as a high-quality feed in aquaculture and fisheries and is considered a delicacy in some areas of Asia.However,it has experienced a marked reduction in recent years due to overexploitation as well as changes in the environment and climate.Here,to comprehensively understand its genetic background and thus provide insights for better conservation and utilization of this species,we assessed the genetic variability and demographic history of T.heterochaetus individuals sampled from eight locations along the coasts of southeast China and north Vietnam based on mitochondrial cytochrome c oxidase I(COI)sequences.We observed high haplotype diversity(Hd),with an average of 0.926,but relatively low nucleotide diversity(π),with a mean of 0.032 across all samples.A total of 94 polymorphic sites and 85 haplotypes were identified among 320 individuals.The pairwise genetic distances among haplotypes ranged from 0.001 to 0.067,with the high intraspecific divergence possibly reflecting geographic isolation and gene pool fragmentation.Significant genetic structures were revealed among the studied locations;specifically,the eight locations could be treated as six genetically different populations based on pairwiseΦST results(0.026–0.951,P<0.01).A significant pattern of isolation-by-distance was detected between the genetic and geographic distances(r=0.873,P=0.001).Three geographic lineages were defined based on phylogenetic tree and network analyses of COI haplotypes.AMOVA results indicated that genetic variations mainly occurred among the three lineages(89.96%).Tests of neutrality and mismatch distribution suggested that T.heterochaetus underwent recent population expansion.These results provide the first report on the genetic status of T.heterochaetus and will be valuable for the management of genetic resources and better understaTylorrhynchus heterochaetus is a widespread benthic polychaete worm found in coastal brackish waters of the west Pacific. It has high ecological and economic value as a biomarker of water quality and as a high-quality feed in aquaculture and fisheries and is considered a delicacy in some areas of Asia.However, it has experienced a marked reduction in recent years due to overexploitation as well as changes in the environment and climate. Here, to comprehensively understand its genetic background and thus provide insights for better conservation and utilization of this species, we assessed the genetic variability and demographic history of T.heterochaetus individuals sampled from eight locations along the coasts of southeast China and north Vietnam based on mitochondrial cytochrome c oxidase Ⅰ(COI) sequences. We observed high haplotype diversity(Hd), with an average of 0.926,but relatively low nucleotide diversity(π), with a mean of 0.032 across all samples. A total of 94 polymorphic sites and 85 haplotypes were identified among 320 individuals. The pairwise genetic distances among haplotypes ranged from 0.001 to0.067, with the high intraspecific divergence possibly reflecting geographic isolation and gene pool fragmentation. Significant genetic structures were revealed among the studied locations; specifically,the eight locations could be treated as six genetically different populations based on pairwise ΦST results(0.026–0.951, P<0.01). A significant pattern of isolation-by-distance was detected between the genetic and geographic distances(r=0.873,P=0.001). Three geographic lineages were defined based on phylogenetic tree and network analyses of COI haplotypes. AMOVA results indicated that genetic variations mainly occurred among the three lineages(89.96%). Tests of neutrality and mismatch distribution suggested that T. heterochaetus underwent recent population expansion. These results provide the first report on the genetic status of T. heterochaetus and will be valuable for the management of genetic resou

关 键 词：Tylorrhynchus heterochaetus Mitochondrial DNA Genetic diversity Population structure Demographic history 

分 类 号：Q953[生物学—动物学]