Molecular Phylogeography Of Fenneropenaeus Merguiensis In The Southeastern Coastal Of China

Fenneropenaeus merguiensis is the economic species of fishery ecosystems in the Southeastern coastal of China. Recent years, with the vigorous development of the Litopenaeus vannamei farming, problems gradually increased, such as the expensive broodstock, the reduced germplasm, the intensified diseases, which influenced the benefit seriously. Therefore, the search for alternative varieties to ensure the quantity of output shrimp industry is a priority. From the 1970 s, China began to study the Fenneropenaeus merguiensis about its embryonic development, breeding and other technologies. Fenneropenaeus merguiensis has been widespread concern of farmers because its easyly captured, cheap price, disease resistance and other advantages.But untill now, we lack of clarity understandings of the Fenneropenaeus merguiensis in Southeast coast of China about its genetics property. So we collected samples of natural populations of Fenneropenaeus merguiensis, using mitochondrial markers and microsatellite markers to study this species about its population genetic structure.We isolated and characterized polymorphic microsatellite loci in Fenneropenaeus merguiensis using RAD-seq. 23 polymorphism loci were obtained. The numbers of alleles per locus ranged from 3 to 16. The observed and expected heterozygosities ranged from 0.2188-1.0000 and from 0.4430-0.8819. The Hardy-Weinberg equilibrium results revealed that 5 loci deviation from Hardy-Weinberg equilibrium. Only 4 loci showed polymorphism(0.25 < PIC < 0.5), and the rest showed highly polymorphic(PIC > 0.5).9 geographic populations of Fenneropenaeus merguiensis were sampled from the coast of China. Mitochondrial DNA Control Region was analysed. Results showed that Fenneropenaeus merguiensis population had high haplotype diversity(0.9958±0.0010) and nucleotide diversity(0.021798±0.010897). Topologies of neighbour-joining tree were shallow and showed that significant genealogical structure corresponding to sampling locations existed. Two Branches exists in the studied areas, the Gulf of Tokin(GOT) ant the others(Clade I), the GOT contains LG population, BH populatin, QS populatin, and the Clade I contains the rest. No Significant genetic differentations were detected among the 9 population based on the AMOVA, pair-wise Fst. Neutrality tests and mismatch distribution showed population expansion in Fenneropenaeus merguiensis. We calculate the time of its expansion. It was about 115,559-39,518 yr ago.Subsequently, we analyzed variation at 16 microsatellite loci among 9 samples of Fenneropenaeus merguiensis. All the populations analyzed displayed high genetic diversity(He = 0.5557~0.6870), Genetic differentiation index(FST) and AMOVA analysis reveal that the genetic differentiation within populations was relatively low, About 2.25% genetic variation was derived from inter-populations, while 97.75% variation was derived from intra-population. Pairwise FST values were generally low. Individual allocation analysis revealed that the 7 population almost carry the same degree of each assumed population features, excepted the gulf of tokin region(BH populatin, QS populatin). Those results revealed that there are two populations exist in these regions.