Molecular Genetics Diversity And Phylogeography Of Oriental River Prawn Macrobrachium Nipponense Populations In Huaihe River Basin

Oriental river prawn, Macrobrachium nipponense, is the most importantcommercial freshwater prawn in China. Huaihe River basin is abundant of the speciesand is also one of the main farming areas in China. In the past two decades, the wildgenetic resource of the species has decreased hardly due to the wrecking habit andshortage of scienctific administration. So, genetic resources study of M. nipponense inHuaihe River basin would be important for its further and better conservation, stockimprovement and increase of farming and wild yileds. In this paper,17wild M.nipponense populations (Bangang, Chengdong, zhengyangguan, Jiaogang, Huajiahu,Wabuhu, Gaotanghu, Qianhe, Tianhe, Huayuanhu, Wuhe, Nvshanhu, Laozishan, Jinhu,Jieshou, Gaoyou, and Shaobohu) were sampled in Huaihe River basin, and the geneticstructure and phlogeography were analyzed using13polymorphic microsatellite (SSR)markers and31mitochondrial Cytochrome Oxidase Subunit I (COI) haplotypes. Maincontents are as follows.1．Genetic diversity of17M. nipponense populations in Huaihe River basin based onmicrosatellitesAmong the total221microsatellite loci from17populations with each45individuals,192loci displayed heterozygosity deficiency and obvious deviation fromHardy-Weinberg equilibrium after Bonferroni correction. The mean expectedheterozygosity values of the17populations were all below0.716, displaying a lowgenetic diversity, while higher genetic diversity appeared in NS(Nvshan) andSB(Shaobo) population, and lower in ZY(Zhengyang)and GT(Gaotang) population. The17population departure from mutation-drift equilibrium, suggesting that the populationstructure had experienced bottleneck effect and the population amount had declined.The AMOVA analysis across all the populations showed that the genetic divergenceamong the17populations was at a lower level.95.87%of the genetic variation camefrom intra-population, and4.13%came from inter-population. The populations of themiddle Huaihe River formed one group and the populations of the lower Huaihe River formed the other group. This suggesting that all the M. nipponense populations ofmiddle Huaihe River in Anhui section could be protected and managed as a single unit,which provides basic material for development and utilization of germplasm resonrcesof M. nipponense.2．Molecular Genetic Diversity and Phylogeography of wild M. nipponense Populationsin Huaihe River basin based on Mitochondrial COI SequenceMitochondrial COI gene with623base pairs fragment from total248individuals ofthe17populations with each10-19individuals were sequenced using LCO1492andHCO2198primers. Among all the COI genes of all the individuals,48variablenucleotides were detected, and31haplotypes with12haplotypes shared were found in17populations. The result of haplotypic and nucleotide diversity analysis displayed amiddle genetic diversity. AMOVA analysis across all populations showed that the therewere low levels of genetic divergences among the17populations (FST=0.0413,P<0.05). The Kimura2-paramter genetic distance between Wuhe and Jiaogang, Huajia,Wabu populations (DA=0.014) was higher than that between other populations.UPGMA tree and haplotype network based on the31haplotypes indicated that thepopulations of the lower Huaihe River formed one clade and the populations of themiddle Huaihe River formed the two others. The biomodel mismatch distribution ofpairwise haplotype difference and the neutrality tests showed that population expansionhas been occurred. All the study results would offer theoretical direction for theprotection and utilization of the M.nipponense in Huaihe River basin.