Acessibilidade / Reportar erro

Genetic diversity of eight wild populations of Pampus argenteus along the coast of China inferred from fifteen polymorphic microsatellite markers

Abstract

Pampus argenteus (Perciformes: Stromateidae) is widely distributed along the coast of China, Indian Ocean, Arabian Gulf and North Sea. Due to overfishing and environmental degradation, its resources reduced year after year. Thus, new management strategies are urgently needed for the sustainable growth and utilization of this species. Characterization of the genetic variation of this fish species is essential for conserving the genetic resource and restraining the population decline. Therefore, it is necessary to have a clear understanding of the intraspecific genetic diversity and population structure of the species. In this study, we assess the genetic diversity and population structure of P. argenteus by using microsatellites. We genotyped 240 P. argenteus individuals from eight wild populations collected from Shidao (SD), Lianyungang (LYG), Lvsi (LS), Zhoushan (ZS), Dongtou (DT), Xiapu (XP), Haikou (HK), and Beibuwan (BBW) along the coast of China using fifteen polymorphic microsatellites. A total of 139 alleles were determined at 15 loci across the eight populations, and a relatively high level of genetic diversity was observed, with observed heterozygosity (Ho) and expected heterozygosity (He) ranging from 0.100 to 1.000, and from 0.669 to 0.934 per locus-location combination, respectively. LS had the highest average allele (number of alleles, A=15.200), and HK the lowest (A=13.000). Hos of P. argenteus are less than Hes, indicating lack of heterozygote within populations. Analysis of molecular variance (AMOVA) showed that most variation (95.66%) occurred within populations, suggesting that this is the main source of total variance. This study will provide useful information for conservation and sustainable exploitation of this important fishery resource.

Descriptors:
Pampus argenteus; microsatellite; genetic diversity; population structure

INTRODUCTION

Pampus argenteus (Perciformes: Stromateidae) is an economically important benthopelagic fish, which is widely distributed along the coast of China, Indian Ocean, Arabian Gulf and North Sea (Davis and Wheeler, 1985DAVIS, P. & WHEELER, A. 1985. The occurrence of Pampus argenteus (Euphrasen, 1788), (Osteichthyes, Perciformes, Stromateoidei, Stromateidae) in the North Sea. Journal of Fish Biology, 26, 105-109.; Liu et al., 2002LIU, J., LI, C. S. & LI, X. S. 2002. Phylogeny and biogeography of Chinese pomfret fishes (Pisces: Stromateidae). Studia Marina Sinica, 44, 235-239. [In Chinese]). Due to overfishing and environmental degradation, its numbers reduced year after year (Jin et al., 2005JIN, X., ZHAO, X., MENG, T. & CUI, Y. M. 2005. Biology Resources and Habitat Environment in Yellow and Bohai Seas, Beijing, Science Press. [In Chinese]; Zhang et al., 2007ZHANG, Q. H., CHENG, J. H., XU, H. X. & ZHENG, Y. J. 2007. Fishery Resources and Its Sustainable Utilization in the East China Sea Region, Shanghai, Fudan University Press. [In Chinese]). Thus, new management strategies are urgently needed for the sustainable growth and utilization of this species. For effective fishery management, we need a mass of biological and evolutionary data. Characterization of the genetic variation of this fish species is essential for conserving the genetic resource and restraining the population decline. Therefore, it is necessary to have a clear understanding of the intraspecific genetic diversity and population structure of the species.

Genetic diversity and population structure have vital importance in understanding and managing populations (Palumbi, 2003PALUMBI, S. R. 2003. Population genetics, demographic connectivity, and the design of marine reserves. Ecological Applications, 13, 146-158.; Muths et al., 2009MUTHS, D., GREWE, P., JEAN, C. & BOURJEA, J. 2009. Genetic population structure of the Swordfish (Xiphias gladius) in the southwest Indian Ocean: Sex-biased differentiation, congruency between markers and its incidence in a way of stock assessment. Fisheries Research, 97, 263-269.). So far, several studies on genetic diversity and population structure of P. argenteus have been reported (Xu et al., 2008XU, G. P., LI, X. G., ZHONG, X. M., LIU, P. T. & TANG, J. H. 2008. Research on genetic diversity of Pampus argentells population in Jiangsu Province by isozyme and ISSR. Jiangsu Agricultural Sciences, 36, 80-82. [In Chinese]; Peng et al., 2010PENG, S. M., SHI, Z. H. & HOU, J. L. 2010. Comparative analysis on the genetic diversity of cultured and wild silver pomfret populations based on mtD-loop and COI gene. Journal of Fisheries of China, 34, 19-25. [In Chinese]; Meng et al., 2009MENG, Y. Y., ZHANG, L. Z., ZHAO, F., SHI, Z. H. & ZHUANG, P. 2009. Preliminary study on the genetic diversity of four geographic populations of silver pomfret (Pampus argenteus). Marine Fisheries, 31, 48-52. [In Chinese]; Wu et al., 2012WU, R. X., LIANG, X. H. & ZHUANG, Z. M. 2012. Mitochondrial COI sequance variation of silver pomfret (Pampus argenteus) from Chinese coastal waters. Acta Zootaxonomica Sinica, 37, 480-488. [In Chinese]; Zhao et al., 2011aZHAO, F., DONG, Y., ZHUANG, P., ZHANG, T., ZHANG, L. Z. & SHI, Z. H. 2011a. Genetic diversity of silver pomfret (Pampus argenteus) in the Southern Yellow and East China Seas. Biochemical Systematics and Ecology, 39, 145-150.). The markers used were mitochondrial DNA COI, D-loop, RAPD, and isozyme. No studies based on microsatellites of P. argenteus is yet available.

Microsatellites or simple sequence repeats (SSR) are short (1-6 bp) repetitive DNA sequences that are highly abundant and almost evenly distributed in genomes. They are generally neutral, highly polymorphic, co-dominant and easily scored with PCR (Goldstein and Schlotterer, 1999GOLDSTEIN, D. B. & SCHLOTTERER, C. 1999. Microsatellites: Evolution and Applications, Oxford, Oxford University Press.). As a more variable marker than RFLP and RAPD, microsatellites have been widely used for population genetics, genome mapping, ecology, and evolution of animals including fishery species for several decades (Goldstein and Schlotterer, 1999GOLDSTEIN, D. B. & SCHLOTTERER, C. 1999. Microsatellites: Evolution and Applications, Oxford, Oxford University Press.; Herwerden et al., 1999HERWERDEN, L. V., BLAIR, D. & AGATSUMA, T. 1999. Genetic diversity in parthenogenetic triploid Paragonimus westermani. International Journal for Parasitology, 29, 1477-1482.; Liu and Cordes, 2004LIU, Z. J. & CORDES, J. F. 2004. DNA marker technologies and their applications in aquaculture genetics. Aquaculture, 238, 1-137.; Vargas-Caro et al., 2017VARGAS-CARO, C., BUSTAMANTE, C., BENNETT, M. B. & OVENDEN, J. R. 2017. Towards sustainable fishery management for skates in South America: The genetic population structure of Zearaja chilensis and Dipturus trachyderma (Chondrichthyes, Rajiformes) in the south-east Pacific Ocean. PLoS One, 12, e0172255.; Kiper et al., 2018KIPER, I. E., BLOOMER, P., BORSA, P. & HOAREAU, T. B. 2018. Characterization of genome-wide microsatellite markers in rabbitfishes, an important resource for artisanal fisheries in the Indo-West Pacific. Molecular Biology Reports, 45, 19-25.).

Population structure is an important factor that should be taken into account by the appropriate regulatory authorities when considering sustainable applications of fish. The aim of this research was to examine the genetic diversity and population structure of P. argenteus along the coast of China to provide useful genetic information for the management of this species. In the present study, we used fifteen polymorphic microsatellite markers to assess the genetic diversity and population structure of eight wild populations of P. argenteus along the coast of China. This study provide useful information for better understanding the evolution potential and population structure of P. argenteus, and is good for the protection and reasonable utilization of this species.

MATERIALS AND METHODS

Sampling and DNA extraction

From June to August, 2013, a total of 240 wild P. argenteus individuals, i.e., 30 individuals of each population, were collected from eight locations along the coast of China (Figure 1). The eight locations are Shidao (SD) of Shandong Province, Lianyungang (LYG) and Lvsi (LS) of Jiangsu Province, Zhoushan (ZS) and Dongtou (DT) of Zhejiang Province, Xiapu (XP) of Fujian Province, Haikou (HK) of Hainan Province, and Beibuwan (BBW) of Guangxi Zhuang Autonomous Region, respectively. The vouchers of the sampled population were deposited in the herbarium of East China Sea Fisheries Research Institute. All individuals were transferred to the laboratory in dry ice and then stored at -80℃ before DNA extraction.

Figure 1
Map of the P. argenteus sampled locations (indicated by circles). The abbreviations correspond to sampled location names, as indicated in text.

Total genomic DNA was extracted from muscle tissue of P. argenteus using the standard proteinase K/phenol/chloroform procedure (Sambrook et al., 1989SAMBROOK, J., FRITSCH, E. F. & MANIATIS, T. 1989. Molecular cloning: a laboratory manual, New York, Cold Spring Harbor Laboratory Press.). The quality of the extracted DNA was checked using 0.8% agarose gel electrophoresis, then stored at -20°C for PCR amplification.

Microsatellite genotyping

Twenty-six pairs of novel polymorphic microsatellite markers for P. argenteus were isolated using combined biotin capture method. Fifteen of them, i.e., YC79, YC90, YC140, YC275, YC339, YC353-1, YC353-2, YC459, YC687, YC705, YC731, YC742, YC754, YC764, and YC792 (Table 1), were used for genotyping all the 240 P. argenteus individuals. Polymerase chain reaction (PCR) amplification was performed in a 15 µL reaction volume containing approximately 10-50 ng of genomic DNA, 0.6 µM of each primer, 7.5 µL 2 ×Taq PCR MasterMix (TIANGEN), with the following thermal cycling conditions: an initial denaturation at 94°C for 3 min, followed by 35 cycles of denaturing at 94°C for 30 s, annealing at primer-specific annealing temperature (Ta, see Table 1) for 30 s, elongation at 72°C for 30 s, followed by a final extension at 72°C for 7 min. The final PCR products were separated by electrophoresis in denaturing 6% polyacrylamide gels and visualized by silver staining. The allele sizes were estimated with a 10 bp DNA ladder (Invitrogen) as reference.

Table 1
Characterization of fifteen microsatellite loci used in this study.

Statistical analysis

Measurements of genetic diversity

The number of alleles (A), number of effective alleles (Ae), observed heterozygosity (Ho), expected heterozygosity (He), and the inbreeding coefficient (FIS) for each locus from each population were obtained using GenAlEx 6.0 (Peakall and Smouse, 2006PEAKALL, R. & SMOUSE, P. E. 2006. GENALEX 6: genetic analysis in Excel. Population genetic software for teaching and research. Molecular Ecology Resources, 6, 288-295.). The diversity level of each genetic locus was evaluated with polymorphic information content (PIC) using the CERVUS version 3.0.3 (Marshall et al., 1998MARSHALL, T. C., SLATE, J., KRUUK, L. E. B. & PEMBERTON, J. M. 1998. Statistical confidence for likelihood-based paternity inference in natural populations. Molecular Ecology, 17, 639-655.). GENEPOP on the Web (http://genepop.curtin.edu.au/, Raymond and Rousset, 1995RAYMOND, M. & ROUSSET, F. 1995. Genepop (version-1.2): Population genetics software for exact tests and ecumenicism. Journal of Heredity, 86, 248-249.) was used to check the deviations from Hardy-Weinberg equilibrium (HWE) and Linkage Disequilibrium (LD) of each locus within each site. HWE and LD tests were performed using the Markov Chain method (10,000 dememorization steps, 100 batches, 5000 iterations).

Measurements of population differentiation

To study population structure, population-level pairwise FST was analyzed using a permutation with 10,000 replicates. Analysis of molecular variance (AMOVA) were calculated using software ARLEQUIN 3.1 (Excoffier et al., 2005EXCOFFIER, L., LAVAL, G. & SCHNEIDER, S. 2005. Arlequin version 3.0: An integrated software package for population genetics data analysis. Evolutionary Bioinformatics, 1, 47-50.). To examine the genetic relationships among populations, the matrix of Nei's genetic distance of pairwise locations (Nei, 1978NEI, M. 1978. Estimation of average heterozygosity and genetic distance from a small number of individuals. Genetics, 89, 583-590.) was calculated using the GenAlEx 6.0 (Peakall and Smouse, 2006PEAKALL, R. & SMOUSE, P. E. 2006. GENALEX 6: genetic analysis in Excel. Population genetic software for teaching and research. Molecular Ecology Resources, 6, 288-295.). Then an unweighted pair-group mean analysis (UPGMA) tree was constructed based on Nei's genetic distance matrices using MEGA version 5.0 software (Tamura et al., 2011TAMURA, K., PETERSON, D., PETERSON, N., STECHER, G., NEI, M. & KUMAR, S. 2011. MEGA5: Molecular Evolutionary Genetics Analysis Using Maximum Likelihood, Evolutionary Distance, and Maximum Parsimony Methods. Molecular Biology and Evolution, 28, 2731-2739.). In order to provide a visual representation of population subdivision, Principal Component Analysis (PCA) was performed in GenAlEx 6.0 (Peakall and Smouse, 2006PEAKALL, R. & SMOUSE, P. E. 2006. GENALEX 6: genetic analysis in Excel. Population genetic software for teaching and research. Molecular Ecology Resources, 6, 288-295.).

Demographical Bottleneck

We detect recent population declines by computing the heterozygosity excess statistic using the computer program BOTTLENECK with two methods (Cornuet and Luikart, 1996CORNUET, J. M. & LUIKART, G. 1996. Description and power analysis of two tests for detecting recent population bottlenecks from allele frequency data. Genetics, 144, 2001-2014.). The first method basing on the principle of heterozygosity excess was executed under two different mutation models: two-phase mutation model (TPM) and stepwise mutation model (SMM), where 95% and 90% single-step mutations, and 5% and 10% multiple steps mutations with 1,000 simulation iterations were set as recommended by Piry et al. (1999)PIRY, S., LUIKART, G. & CORNUET, J. M. 1999. BOTTLENECK: a computer program for detecting recent reductions in the effective population size using allele frequency data. Journal of Heredity, 90, 502-503.. SMM was used because microsatellite loci appear to evolve under a mutation model that is more similar to the SMM than the infinite allele model (IAM) (Valdes et al., 1993VALDES, A. M., SLATKIN, M. & FREIMER, N. B. 1993. Allele frequencies at microsatellite loci: the stepwise mutation model revisited. Genetics, 133, 737-749.; Shriver et al., 1993SHRIVER, M. D., JIN, L., CHAKRABORTY, R. & BOERWINKLE, E. 1993. Vntr Allele Frequency Distributions under the Stepwise Mutation Model: A Computer Simulation Approach. Genetics, 134, 983-993.). The second method, mode-shift test (Luikart and Cornuet, 1998LUIKART, G. & CORNUET, J. M. 1998. Empirical Evaluation of a Test for Identifying Recently Bottlenecked Populations from Allele Frequency Data. Conservation Biology, 12, 228-237.), was used to detect a potential bottlenecked population using an L-shaped distribution of allele frequency as mutation-drift equilibrium.

RESULTS

Genetic diversity

All the 15 microsatellite markers were well amplified in the eight populations of P. argenteus. Of the 120 HWE tests across all 15 loci, 38 were conformed to HWE (Table Sup Supplementary Table Table Sup Statistics for genetic variation at 15 microsatellite loci in eight populations of P. argenteus. Locus Population Parameters A Ae Ho He PIC PHWE Fis YC79 SD 17 13.333 0.567 0.925 0.920 0.0000 * 0.387 LYG 14 9.524 0.767 0.895 0.886 0.0019 0.143 LS 17 13.636 0.767 0.927 0.922 0.0040 0.173 ZS 16 12.950 0.667 0.923 0.917 0.0004 0.278 DT 16 12.245 0.533 0.918 0.913 0.0000 * 0.419 XP 16 10.169 0.767 0.902 0.894 0.0526 0.150 HK 10 7.531 0.433 0.867 0.853 0.0000 * 0.500 BBW 12 9.278 0.433 0.892 0.882 0.0000 * 0.514 YC90 SD 15 12.500 0.333 0.920 0.914 0.0000 * 0.638 LYG 15 9.836 0.333 0.898 0.890 0.0000* 0.629 LS 14 11.613 0.533 0.914 0.907 0.0000* 0.416 ZS 15 10.588 0.400 0.906 0.898 0.0000* 0.558 DT 14 11.111 0.667 0.910 0.903 0.0025 0.267 XP 16 10.227 0.533 0.902 0.894 0.0000 * 0.409 HK 12 8.571 0.367 0.883 0.872 0.0000* 0.585 BBW 11 8.451 0.300 0.882 0.870 0.0000* 0.660 YC140 SD 16 9.184 0.733 0.891 0.882 0.0008 0.177 LYG 19 14.516 0.867 0.931 0.927 0.0042 0.069 LS 19 13.433 0.833 0.926 0.921 0.0001 0.100 ZS 17 10.843 0.800 0.908 0.901 0.0621 0.119 DT 19 12.766 0.833 0.922 0.916 0.3156 0.096 XP 13 8.000 0.433 0.875 0.863 0.0000 * 0.505 HK 12 4.972 0.533 0.799 0.781 0.0000 * 0.332 BBW 12 4.700 0.533 0.787 0.761 0.0000* 0.323 YC275 SD 18 11.921 0.800 0.916 0.910 0.0000* 0.127 LYG 20 15.126 0.833 0.934 0.930 0.0000* 0.108 LS 21 13.043 0.867 0.923 0.918 0.1694 0.061 ZS 17 13.534 0.833 0.926 0.921 0.0593 0.100 DT 20 14.876 0.900 0.933 0.929 0.0226 0.035 XP 15 7.531 0.733 0.867 0.856 0.0000* 0.154 HK 18 13.235 1.000 0.924 0.919 0.0000 * -0.082 BBW 18 10.843 0.933 0.908 0.901 0.0000 * -0.028 YC339 SD 11 6.844 0.300 0.854 0.838 0.0000 * 0.649 LYG 12 7.895 0.600 0.873 0.862 0.0000* 0.313 LS 12 8.612 0.333 0.884 0.873 0.0000* 0.623 ZS 11 8.867 0.533 0.887 0.877 0.0000* 0.399 DT 13 7.759 0.467 0.871 0.858 0.0000 * 0.464 XP 11 8.333 0.633 0.880 0.868 0.0002 0.280 HK 11 6.475 0.267 0.846 0.829 0.0000* 0.685 BBW 12 7.792 0.400 0.872 0.859 0.0000* 0.541 YC353-1 SD 18 12.245 0.733 0.918 0.913 0.0230 0.201 LYG 19 13.534 0.733 0.926 0.921 0.0001 0.208 LS 21 14.754 0.833 0.932 0.928 0.0077 0.106 ZS 19 12.857 0.633 0.922 0.917 0.0001 0.313 DT 19 13.433 0.633 0.926 0.921 0.0000 * 0.316 XP 13 7.792 1.000 0.872 0.859 0.0110 -0.147 HK 14 7.895 0.767 0.873 0.861 0.0005 0.122 BBW 16 9.783 0.900 0.898 0.889 0.4368 -0.002 YC353-2 SD 11 6.642 0.467 0.849 0.833 0.0000 * 0.451 LYG 11 8.295 0.733 0.879 0.868 0.0089 0.166 LS 14 8.696 0.433 0.885 0.875 0.0000 * 0.510 ZS 18 10.345 0.600 0.903 0.897 0.0000* 0.336 DT 16 10.465 0.467 0.904 0.897 0.0000* 0.484 XP 11 6.569 0.733 0.848 0.831 0.0002 0.135 HK 11 6.923 0.667 0.856 0.841 0.0006 0.221 BBW 12 8.295 0.800 0.879 0.868 0.0938 0.090 YC459 SD 10 5.902 0.400 0.831 0.810 0.0000 * 0.518 LYG 9 3.766 0.367 0.734 0.698 0.0000 * 0.501 LS 12 5.085 0.500 0.803 0.787 0.0000* 0.378 ZS 7 3.358 0.267 0.702 0.654 0.0000* 0.620 DT 6 3.025 0.367 0.669 0.618 0.0000* 0.452 XP 10 6.000 1.000 0.833 0.813 0.0000* -0.200 HK 15 8.451 0.167 0.882 0.871 0.0000* 0.811 BBW 12 5.248 0.267 0.809 0.792 0.0000* 0.671 YC687 SD 14 10.588 0.233 0.906 0.898 0.0000 * 0.742 LYG 18 9.677 0.300 0.897 0.888 0.0000 * 0.665 LS 14 11.250 0.400 0.911 0.904 0.0000* 0.561 ZS 18 12.000 0.467 0.917 0.911 0.0000* 0.491 DT 18 11.250 0.567 0.911 0.905 0.0000* 0.378 XP 20 11.921 0.633 0.916 0.910 0.0000* 0.309 HK 6 4.327 0.100 0.769 0.733 0.0000* 0.870 BBW 9 5.696 0.200 0.824 0.803 0.0000* 0.757 YC705 SD 18 13.043 0.633 0.923 0.918 0.0000* 0.314 LYG 18 10.976 0.633 0.909 0.902 0.0000* 0.303 LS 19 13.433 0.633 0.926 0.921 0.0000* 0.316 ZS 18 13.235 0.733 0.924 0.919 0.0002 0.207 DT 17 14.876 0.800 0.933 0.929 0.1004 0.142 XP 20 14.063 0.633 0.929 0.924 0.0000 * 0.318 HK 20 14.400 0.700 0.931 0.926 0.0000 * 0.248 BBW 22 14.754 0.833 0.932 0.928 0.0067 0.106 YC731 SD 13 9.890 0.600 0.899 0.890 0.0000 * 0.333 LYG 13 9.626 0.200 0.896 0.887 0.0000 * 0.777 LS 13 8.531 0.433 0.883 0.872 0.0000* 0.509 ZS 15 10.112 0.533 0.901 0.893 0.0000* 0.408 DT 11 8.612 0.467 0.884 0.873 0.0000* 0.472 XP 10 5.625 0.400 0.822 0.801 0.0000* 0.514 HK 8 6.186 0.167 0.838 0.819 0.0000 * 0.801 BBW 13 8.295 0.267 0.879 0.867 0.0000* 0.697 YC742 SD 9 4.523 0.233 0.779 0.754 0.0000* 0.700 LYG 9 6.767 0.300 0.852 0.835 0.0000* 0.648 LS 10 5.751 0.633 0.826 0.804 0.0000* 0.233 ZS 12 6.792 0.700 0.853 0.836 0.0009 0.179 DT 9 5.471 0.700 0.817 0.792 0.0343 0.143 XP 9 3.956 0.167 0.747 0.717 0.0000 * 0.777 HK 12 6.792 0.533 0.853 0.837 0.0000* 0.375 BBW 12 6.250 0.433 0.840 0.821 0.0000* 0.484 YC754 SD 9 6.818 0.633 0.853 0.837 0.0007 0.258 LYG 12 6.383 0.300 0.843 0.826 0.0000 * 0.644 LS 11 5.202 0.567 0.808 0.788 0.0000* 0.298 ZS 10 5.263 0.500 0.810 0.788 0.0000* 0.383 DT 10 4.775 0.700 0.791 0.761 0.1399 0.115 XP 11 7.059 0.433 0.858 0.842 0.0000* 0.495 HK 16 10.526 0.633 0.905 0.898 0.0000* 0.300 BBW 12 8.451 0.700 0.882 0.871 0.0502 0.206 YC764 SD 21 15.652 0.767 0.936 0.932 0.0058 0.181 LYG 19 12.500 0.633 0.920 0.915 0.0000 * 0.312 LS 18 9.890 0.600 0.899 0.891 0.0000* 0.333 ZS 15 10.651 0.400 0.906 0.899 0.0000* 0.559 DT 18 13.043 0.667 0.923 0.918 0.0000* 0.278 XP 17 12.000 0.700 0.917 0.911 0.0000* 0.236 HK 14 8.036 0.533 0.876 0.864 0.0002 0.391 BBW 13 9.375 0.500 0.893 0.884 0.0000* 0.440 YC792 SD 14 8.451 0.533 0.882 0.872 0.0000* 0.395 LYG 12 7.115 0.400 0.859 0.844 0.0000* 0.535 LS 13 8.911 0.533 0.888 0.877 0.0000* 0.399 ZS 13 7.500 0.467 0.867 0.854 0.0000* 0.462 DT 15 9.626 0.633 0.896 0.888 0.0003 0.293 XP 13 8.036 0.267 0.876 0.864 0.0000* 0.695 HK 16 10.778 0.700 0.907 0.900 0.0011 0.228 BBW 16 11.538 0.700 0.913 0.907 0.0001 0.234 All locus SD 14.267 9.836 0.531 0.885 0.875 0.0038 0.405 LYG 14.667 9.702 0.533 0.883 0.872 0.0024 0.401 LS 15.200 10.123 0.593 0.889 0.879 0.0139 0.334 ZS 14.733 9.926 0.569 0.884 0.872 0.0165 0.361 DT 14.733 10.222 0.627 0.881 0.868 0.0441 0.290 XP 13.667 8.485 0.604 0.870 0.857 0.0057 0.309 HK 13.000 8.340 0.504 0.867 0.854 0.0004 0.426w BBW 13.467 8.583 0.547 0.873 0.860 0.0430 0.379 A = the number of alleles per locus, Ae = the number of effective alleles per locus, PIC = polymorphism information content, Ho = observed heterozygosity, He = expected heterozygosity, FIS = the inbreeding coefficient (*, significantly value of HWE greater than zero after sequential Bonferroni corrections). ) within each sample location after applying sequential Bonferroni corrections (minimum adjusted alpha = 0.00050) (Rice, 1989RICE, W. R. 1989. Analyzing tables of statistical tests. Evolution, 43, 223-225.). In addition, significant genotypic LD for multiple comparisons of 15 loci within populations was detected in 18 out of 1680 tests (minimum adjusted alpha = 0.00015) (Rice, 1989RICE, W. R. 1989. Analyzing tables of statistical tests. Evolution, 43, 223-225.) after sequential Bonferroni correction. Thus, we think that most microsatellite loci could be deemed as genetically independent for further analysis.

All 15 loci were polymorphic in all of the eight studied populations of P. argenteus with high allelic diversity and heterozygosity (Table Sup. Supplementary Table Table Sup Statistics for genetic variation at 15 microsatellite loci in eight populations of P. argenteus. Locus Population Parameters A Ae Ho He PIC PHWE Fis YC79 SD 17 13.333 0.567 0.925 0.920 0.0000 * 0.387 LYG 14 9.524 0.767 0.895 0.886 0.0019 0.143 LS 17 13.636 0.767 0.927 0.922 0.0040 0.173 ZS 16 12.950 0.667 0.923 0.917 0.0004 0.278 DT 16 12.245 0.533 0.918 0.913 0.0000 * 0.419 XP 16 10.169 0.767 0.902 0.894 0.0526 0.150 HK 10 7.531 0.433 0.867 0.853 0.0000 * 0.500 BBW 12 9.278 0.433 0.892 0.882 0.0000 * 0.514 YC90 SD 15 12.500 0.333 0.920 0.914 0.0000 * 0.638 LYG 15 9.836 0.333 0.898 0.890 0.0000* 0.629 LS 14 11.613 0.533 0.914 0.907 0.0000* 0.416 ZS 15 10.588 0.400 0.906 0.898 0.0000* 0.558 DT 14 11.111 0.667 0.910 0.903 0.0025 0.267 XP 16 10.227 0.533 0.902 0.894 0.0000 * 0.409 HK 12 8.571 0.367 0.883 0.872 0.0000* 0.585 BBW 11 8.451 0.300 0.882 0.870 0.0000* 0.660 YC140 SD 16 9.184 0.733 0.891 0.882 0.0008 0.177 LYG 19 14.516 0.867 0.931 0.927 0.0042 0.069 LS 19 13.433 0.833 0.926 0.921 0.0001 0.100 ZS 17 10.843 0.800 0.908 0.901 0.0621 0.119 DT 19 12.766 0.833 0.922 0.916 0.3156 0.096 XP 13 8.000 0.433 0.875 0.863 0.0000 * 0.505 HK 12 4.972 0.533 0.799 0.781 0.0000 * 0.332 BBW 12 4.700 0.533 0.787 0.761 0.0000* 0.323 YC275 SD 18 11.921 0.800 0.916 0.910 0.0000* 0.127 LYG 20 15.126 0.833 0.934 0.930 0.0000* 0.108 LS 21 13.043 0.867 0.923 0.918 0.1694 0.061 ZS 17 13.534 0.833 0.926 0.921 0.0593 0.100 DT 20 14.876 0.900 0.933 0.929 0.0226 0.035 XP 15 7.531 0.733 0.867 0.856 0.0000* 0.154 HK 18 13.235 1.000 0.924 0.919 0.0000 * -0.082 BBW 18 10.843 0.933 0.908 0.901 0.0000 * -0.028 YC339 SD 11 6.844 0.300 0.854 0.838 0.0000 * 0.649 LYG 12 7.895 0.600 0.873 0.862 0.0000* 0.313 LS 12 8.612 0.333 0.884 0.873 0.0000* 0.623 ZS 11 8.867 0.533 0.887 0.877 0.0000* 0.399 DT 13 7.759 0.467 0.871 0.858 0.0000 * 0.464 XP 11 8.333 0.633 0.880 0.868 0.0002 0.280 HK 11 6.475 0.267 0.846 0.829 0.0000* 0.685 BBW 12 7.792 0.400 0.872 0.859 0.0000* 0.541 YC353-1 SD 18 12.245 0.733 0.918 0.913 0.0230 0.201 LYG 19 13.534 0.733 0.926 0.921 0.0001 0.208 LS 21 14.754 0.833 0.932 0.928 0.0077 0.106 ZS 19 12.857 0.633 0.922 0.917 0.0001 0.313 DT 19 13.433 0.633 0.926 0.921 0.0000 * 0.316 XP 13 7.792 1.000 0.872 0.859 0.0110 -0.147 HK 14 7.895 0.767 0.873 0.861 0.0005 0.122 BBW 16 9.783 0.900 0.898 0.889 0.4368 -0.002 YC353-2 SD 11 6.642 0.467 0.849 0.833 0.0000 * 0.451 LYG 11 8.295 0.733 0.879 0.868 0.0089 0.166 LS 14 8.696 0.433 0.885 0.875 0.0000 * 0.510 ZS 18 10.345 0.600 0.903 0.897 0.0000* 0.336 DT 16 10.465 0.467 0.904 0.897 0.0000* 0.484 XP 11 6.569 0.733 0.848 0.831 0.0002 0.135 HK 11 6.923 0.667 0.856 0.841 0.0006 0.221 BBW 12 8.295 0.800 0.879 0.868 0.0938 0.090 YC459 SD 10 5.902 0.400 0.831 0.810 0.0000 * 0.518 LYG 9 3.766 0.367 0.734 0.698 0.0000 * 0.501 LS 12 5.085 0.500 0.803 0.787 0.0000* 0.378 ZS 7 3.358 0.267 0.702 0.654 0.0000* 0.620 DT 6 3.025 0.367 0.669 0.618 0.0000* 0.452 XP 10 6.000 1.000 0.833 0.813 0.0000* -0.200 HK 15 8.451 0.167 0.882 0.871 0.0000* 0.811 BBW 12 5.248 0.267 0.809 0.792 0.0000* 0.671 YC687 SD 14 10.588 0.233 0.906 0.898 0.0000 * 0.742 LYG 18 9.677 0.300 0.897 0.888 0.0000 * 0.665 LS 14 11.250 0.400 0.911 0.904 0.0000* 0.561 ZS 18 12.000 0.467 0.917 0.911 0.0000* 0.491 DT 18 11.250 0.567 0.911 0.905 0.0000* 0.378 XP 20 11.921 0.633 0.916 0.910 0.0000* 0.309 HK 6 4.327 0.100 0.769 0.733 0.0000* 0.870 BBW 9 5.696 0.200 0.824 0.803 0.0000* 0.757 YC705 SD 18 13.043 0.633 0.923 0.918 0.0000* 0.314 LYG 18 10.976 0.633 0.909 0.902 0.0000* 0.303 LS 19 13.433 0.633 0.926 0.921 0.0000* 0.316 ZS 18 13.235 0.733 0.924 0.919 0.0002 0.207 DT 17 14.876 0.800 0.933 0.929 0.1004 0.142 XP 20 14.063 0.633 0.929 0.924 0.0000 * 0.318 HK 20 14.400 0.700 0.931 0.926 0.0000 * 0.248 BBW 22 14.754 0.833 0.932 0.928 0.0067 0.106 YC731 SD 13 9.890 0.600 0.899 0.890 0.0000 * 0.333 LYG 13 9.626 0.200 0.896 0.887 0.0000 * 0.777 LS 13 8.531 0.433 0.883 0.872 0.0000* 0.509 ZS 15 10.112 0.533 0.901 0.893 0.0000* 0.408 DT 11 8.612 0.467 0.884 0.873 0.0000* 0.472 XP 10 5.625 0.400 0.822 0.801 0.0000* 0.514 HK 8 6.186 0.167 0.838 0.819 0.0000 * 0.801 BBW 13 8.295 0.267 0.879 0.867 0.0000* 0.697 YC742 SD 9 4.523 0.233 0.779 0.754 0.0000* 0.700 LYG 9 6.767 0.300 0.852 0.835 0.0000* 0.648 LS 10 5.751 0.633 0.826 0.804 0.0000* 0.233 ZS 12 6.792 0.700 0.853 0.836 0.0009 0.179 DT 9 5.471 0.700 0.817 0.792 0.0343 0.143 XP 9 3.956 0.167 0.747 0.717 0.0000 * 0.777 HK 12 6.792 0.533 0.853 0.837 0.0000* 0.375 BBW 12 6.250 0.433 0.840 0.821 0.0000* 0.484 YC754 SD 9 6.818 0.633 0.853 0.837 0.0007 0.258 LYG 12 6.383 0.300 0.843 0.826 0.0000 * 0.644 LS 11 5.202 0.567 0.808 0.788 0.0000* 0.298 ZS 10 5.263 0.500 0.810 0.788 0.0000* 0.383 DT 10 4.775 0.700 0.791 0.761 0.1399 0.115 XP 11 7.059 0.433 0.858 0.842 0.0000* 0.495 HK 16 10.526 0.633 0.905 0.898 0.0000* 0.300 BBW 12 8.451 0.700 0.882 0.871 0.0502 0.206 YC764 SD 21 15.652 0.767 0.936 0.932 0.0058 0.181 LYG 19 12.500 0.633 0.920 0.915 0.0000 * 0.312 LS 18 9.890 0.600 0.899 0.891 0.0000* 0.333 ZS 15 10.651 0.400 0.906 0.899 0.0000* 0.559 DT 18 13.043 0.667 0.923 0.918 0.0000* 0.278 XP 17 12.000 0.700 0.917 0.911 0.0000* 0.236 HK 14 8.036 0.533 0.876 0.864 0.0002 0.391 BBW 13 9.375 0.500 0.893 0.884 0.0000* 0.440 YC792 SD 14 8.451 0.533 0.882 0.872 0.0000* 0.395 LYG 12 7.115 0.400 0.859 0.844 0.0000* 0.535 LS 13 8.911 0.533 0.888 0.877 0.0000* 0.399 ZS 13 7.500 0.467 0.867 0.854 0.0000* 0.462 DT 15 9.626 0.633 0.896 0.888 0.0003 0.293 XP 13 8.036 0.267 0.876 0.864 0.0000* 0.695 HK 16 10.778 0.700 0.907 0.900 0.0011 0.228 BBW 16 11.538 0.700 0.913 0.907 0.0001 0.234 All locus SD 14.267 9.836 0.531 0.885 0.875 0.0038 0.405 LYG 14.667 9.702 0.533 0.883 0.872 0.0024 0.401 LS 15.200 10.123 0.593 0.889 0.879 0.0139 0.334 ZS 14.733 9.926 0.569 0.884 0.872 0.0165 0.361 DT 14.733 10.222 0.627 0.881 0.868 0.0441 0.290 XP 13.667 8.485 0.604 0.870 0.857 0.0057 0.309 HK 13.000 8.340 0.504 0.867 0.854 0.0004 0.426w BBW 13.467 8.583 0.547 0.873 0.860 0.0430 0.379 A = the number of alleles per locus, Ae = the number of effective alleles per locus, PIC = polymorphism information content, Ho = observed heterozygosity, He = expected heterozygosity, FIS = the inbreeding coefficient (*, significantly value of HWE greater than zero after sequential Bonferroni corrections). ). A total of 139 alleles were detected at the 15 microsatellite loci across the eight populations. The number of private alleles for the eight populations are 9 (SD), 10 (LYG), 7 (LS), 6 (ZS), 7 (DT), 18 (XP), 18 (HK), and 23 (BBW), respectively. For A, LS was the highest population with A=15.200, while HK was the least variable one with A=13.000. For Ae, DT was the highest with Ae=10.222, while HK was the least with Ae=8.340.

For the eight populations, the average polymorphism information content (PIC) ranged from 0.854 (HK) to 0.879 (LS) per location. The average inbreeding coefficient (FIS) ranged from -0.200 (YC459-XP) to 0.870 (YC687-HK) with an average value 0.363 per locus, and ranged between 0.290 (DT) and 0.426 (HK) for populations (Table Sup. Supplementary Table Table Sup Statistics for genetic variation at 15 microsatellite loci in eight populations of P. argenteus. Locus Population Parameters A Ae Ho He PIC PHWE Fis YC79 SD 17 13.333 0.567 0.925 0.920 0.0000 * 0.387 LYG 14 9.524 0.767 0.895 0.886 0.0019 0.143 LS 17 13.636 0.767 0.927 0.922 0.0040 0.173 ZS 16 12.950 0.667 0.923 0.917 0.0004 0.278 DT 16 12.245 0.533 0.918 0.913 0.0000 * 0.419 XP 16 10.169 0.767 0.902 0.894 0.0526 0.150 HK 10 7.531 0.433 0.867 0.853 0.0000 * 0.500 BBW 12 9.278 0.433 0.892 0.882 0.0000 * 0.514 YC90 SD 15 12.500 0.333 0.920 0.914 0.0000 * 0.638 LYG 15 9.836 0.333 0.898 0.890 0.0000* 0.629 LS 14 11.613 0.533 0.914 0.907 0.0000* 0.416 ZS 15 10.588 0.400 0.906 0.898 0.0000* 0.558 DT 14 11.111 0.667 0.910 0.903 0.0025 0.267 XP 16 10.227 0.533 0.902 0.894 0.0000 * 0.409 HK 12 8.571 0.367 0.883 0.872 0.0000* 0.585 BBW 11 8.451 0.300 0.882 0.870 0.0000* 0.660 YC140 SD 16 9.184 0.733 0.891 0.882 0.0008 0.177 LYG 19 14.516 0.867 0.931 0.927 0.0042 0.069 LS 19 13.433 0.833 0.926 0.921 0.0001 0.100 ZS 17 10.843 0.800 0.908 0.901 0.0621 0.119 DT 19 12.766 0.833 0.922 0.916 0.3156 0.096 XP 13 8.000 0.433 0.875 0.863 0.0000 * 0.505 HK 12 4.972 0.533 0.799 0.781 0.0000 * 0.332 BBW 12 4.700 0.533 0.787 0.761 0.0000* 0.323 YC275 SD 18 11.921 0.800 0.916 0.910 0.0000* 0.127 LYG 20 15.126 0.833 0.934 0.930 0.0000* 0.108 LS 21 13.043 0.867 0.923 0.918 0.1694 0.061 ZS 17 13.534 0.833 0.926 0.921 0.0593 0.100 DT 20 14.876 0.900 0.933 0.929 0.0226 0.035 XP 15 7.531 0.733 0.867 0.856 0.0000* 0.154 HK 18 13.235 1.000 0.924 0.919 0.0000 * -0.082 BBW 18 10.843 0.933 0.908 0.901 0.0000 * -0.028 YC339 SD 11 6.844 0.300 0.854 0.838 0.0000 * 0.649 LYG 12 7.895 0.600 0.873 0.862 0.0000* 0.313 LS 12 8.612 0.333 0.884 0.873 0.0000* 0.623 ZS 11 8.867 0.533 0.887 0.877 0.0000* 0.399 DT 13 7.759 0.467 0.871 0.858 0.0000 * 0.464 XP 11 8.333 0.633 0.880 0.868 0.0002 0.280 HK 11 6.475 0.267 0.846 0.829 0.0000* 0.685 BBW 12 7.792 0.400 0.872 0.859 0.0000* 0.541 YC353-1 SD 18 12.245 0.733 0.918 0.913 0.0230 0.201 LYG 19 13.534 0.733 0.926 0.921 0.0001 0.208 LS 21 14.754 0.833 0.932 0.928 0.0077 0.106 ZS 19 12.857 0.633 0.922 0.917 0.0001 0.313 DT 19 13.433 0.633 0.926 0.921 0.0000 * 0.316 XP 13 7.792 1.000 0.872 0.859 0.0110 -0.147 HK 14 7.895 0.767 0.873 0.861 0.0005 0.122 BBW 16 9.783 0.900 0.898 0.889 0.4368 -0.002 YC353-2 SD 11 6.642 0.467 0.849 0.833 0.0000 * 0.451 LYG 11 8.295 0.733 0.879 0.868 0.0089 0.166 LS 14 8.696 0.433 0.885 0.875 0.0000 * 0.510 ZS 18 10.345 0.600 0.903 0.897 0.0000* 0.336 DT 16 10.465 0.467 0.904 0.897 0.0000* 0.484 XP 11 6.569 0.733 0.848 0.831 0.0002 0.135 HK 11 6.923 0.667 0.856 0.841 0.0006 0.221 BBW 12 8.295 0.800 0.879 0.868 0.0938 0.090 YC459 SD 10 5.902 0.400 0.831 0.810 0.0000 * 0.518 LYG 9 3.766 0.367 0.734 0.698 0.0000 * 0.501 LS 12 5.085 0.500 0.803 0.787 0.0000* 0.378 ZS 7 3.358 0.267 0.702 0.654 0.0000* 0.620 DT 6 3.025 0.367 0.669 0.618 0.0000* 0.452 XP 10 6.000 1.000 0.833 0.813 0.0000* -0.200 HK 15 8.451 0.167 0.882 0.871 0.0000* 0.811 BBW 12 5.248 0.267 0.809 0.792 0.0000* 0.671 YC687 SD 14 10.588 0.233 0.906 0.898 0.0000 * 0.742 LYG 18 9.677 0.300 0.897 0.888 0.0000 * 0.665 LS 14 11.250 0.400 0.911 0.904 0.0000* 0.561 ZS 18 12.000 0.467 0.917 0.911 0.0000* 0.491 DT 18 11.250 0.567 0.911 0.905 0.0000* 0.378 XP 20 11.921 0.633 0.916 0.910 0.0000* 0.309 HK 6 4.327 0.100 0.769 0.733 0.0000* 0.870 BBW 9 5.696 0.200 0.824 0.803 0.0000* 0.757 YC705 SD 18 13.043 0.633 0.923 0.918 0.0000* 0.314 LYG 18 10.976 0.633 0.909 0.902 0.0000* 0.303 LS 19 13.433 0.633 0.926 0.921 0.0000* 0.316 ZS 18 13.235 0.733 0.924 0.919 0.0002 0.207 DT 17 14.876 0.800 0.933 0.929 0.1004 0.142 XP 20 14.063 0.633 0.929 0.924 0.0000 * 0.318 HK 20 14.400 0.700 0.931 0.926 0.0000 * 0.248 BBW 22 14.754 0.833 0.932 0.928 0.0067 0.106 YC731 SD 13 9.890 0.600 0.899 0.890 0.0000 * 0.333 LYG 13 9.626 0.200 0.896 0.887 0.0000 * 0.777 LS 13 8.531 0.433 0.883 0.872 0.0000* 0.509 ZS 15 10.112 0.533 0.901 0.893 0.0000* 0.408 DT 11 8.612 0.467 0.884 0.873 0.0000* 0.472 XP 10 5.625 0.400 0.822 0.801 0.0000* 0.514 HK 8 6.186 0.167 0.838 0.819 0.0000 * 0.801 BBW 13 8.295 0.267 0.879 0.867 0.0000* 0.697 YC742 SD 9 4.523 0.233 0.779 0.754 0.0000* 0.700 LYG 9 6.767 0.300 0.852 0.835 0.0000* 0.648 LS 10 5.751 0.633 0.826 0.804 0.0000* 0.233 ZS 12 6.792 0.700 0.853 0.836 0.0009 0.179 DT 9 5.471 0.700 0.817 0.792 0.0343 0.143 XP 9 3.956 0.167 0.747 0.717 0.0000 * 0.777 HK 12 6.792 0.533 0.853 0.837 0.0000* 0.375 BBW 12 6.250 0.433 0.840 0.821 0.0000* 0.484 YC754 SD 9 6.818 0.633 0.853 0.837 0.0007 0.258 LYG 12 6.383 0.300 0.843 0.826 0.0000 * 0.644 LS 11 5.202 0.567 0.808 0.788 0.0000* 0.298 ZS 10 5.263 0.500 0.810 0.788 0.0000* 0.383 DT 10 4.775 0.700 0.791 0.761 0.1399 0.115 XP 11 7.059 0.433 0.858 0.842 0.0000* 0.495 HK 16 10.526 0.633 0.905 0.898 0.0000* 0.300 BBW 12 8.451 0.700 0.882 0.871 0.0502 0.206 YC764 SD 21 15.652 0.767 0.936 0.932 0.0058 0.181 LYG 19 12.500 0.633 0.920 0.915 0.0000 * 0.312 LS 18 9.890 0.600 0.899 0.891 0.0000* 0.333 ZS 15 10.651 0.400 0.906 0.899 0.0000* 0.559 DT 18 13.043 0.667 0.923 0.918 0.0000* 0.278 XP 17 12.000 0.700 0.917 0.911 0.0000* 0.236 HK 14 8.036 0.533 0.876 0.864 0.0002 0.391 BBW 13 9.375 0.500 0.893 0.884 0.0000* 0.440 YC792 SD 14 8.451 0.533 0.882 0.872 0.0000* 0.395 LYG 12 7.115 0.400 0.859 0.844 0.0000* 0.535 LS 13 8.911 0.533 0.888 0.877 0.0000* 0.399 ZS 13 7.500 0.467 0.867 0.854 0.0000* 0.462 DT 15 9.626 0.633 0.896 0.888 0.0003 0.293 XP 13 8.036 0.267 0.876 0.864 0.0000* 0.695 HK 16 10.778 0.700 0.907 0.900 0.0011 0.228 BBW 16 11.538 0.700 0.913 0.907 0.0001 0.234 All locus SD 14.267 9.836 0.531 0.885 0.875 0.0038 0.405 LYG 14.667 9.702 0.533 0.883 0.872 0.0024 0.401 LS 15.200 10.123 0.593 0.889 0.879 0.0139 0.334 ZS 14.733 9.926 0.569 0.884 0.872 0.0165 0.361 DT 14.733 10.222 0.627 0.881 0.868 0.0441 0.290 XP 13.667 8.485 0.604 0.870 0.857 0.0057 0.309 HK 13.000 8.340 0.504 0.867 0.854 0.0004 0.426w BBW 13.467 8.583 0.547 0.873 0.860 0.0430 0.379 A = the number of alleles per locus, Ae = the number of effective alleles per locus, PIC = polymorphism information content, Ho = observed heterozygosity, He = expected heterozygosity, FIS = the inbreeding coefficient (*, significantly value of HWE greater than zero after sequential Bonferroni corrections). ), suggesting that there is high inbreeding in these eight P. argenteus populations. Observed and expected heterozygosity (Ho and He) ranged from 0.100 to 1.000 and from 0.669 to 0.934 per locus-location combination, while from 0.504 (HK) to 0.627 (DT) and from 0.867 (HK) to 0.889 (LS) per location, respectively (Table Sup. Supplementary Table Table Sup Statistics for genetic variation at 15 microsatellite loci in eight populations of P. argenteus. Locus Population Parameters A Ae Ho He PIC PHWE Fis YC79 SD 17 13.333 0.567 0.925 0.920 0.0000 * 0.387 LYG 14 9.524 0.767 0.895 0.886 0.0019 0.143 LS 17 13.636 0.767 0.927 0.922 0.0040 0.173 ZS 16 12.950 0.667 0.923 0.917 0.0004 0.278 DT 16 12.245 0.533 0.918 0.913 0.0000 * 0.419 XP 16 10.169 0.767 0.902 0.894 0.0526 0.150 HK 10 7.531 0.433 0.867 0.853 0.0000 * 0.500 BBW 12 9.278 0.433 0.892 0.882 0.0000 * 0.514 YC90 SD 15 12.500 0.333 0.920 0.914 0.0000 * 0.638 LYG 15 9.836 0.333 0.898 0.890 0.0000* 0.629 LS 14 11.613 0.533 0.914 0.907 0.0000* 0.416 ZS 15 10.588 0.400 0.906 0.898 0.0000* 0.558 DT 14 11.111 0.667 0.910 0.903 0.0025 0.267 XP 16 10.227 0.533 0.902 0.894 0.0000 * 0.409 HK 12 8.571 0.367 0.883 0.872 0.0000* 0.585 BBW 11 8.451 0.300 0.882 0.870 0.0000* 0.660 YC140 SD 16 9.184 0.733 0.891 0.882 0.0008 0.177 LYG 19 14.516 0.867 0.931 0.927 0.0042 0.069 LS 19 13.433 0.833 0.926 0.921 0.0001 0.100 ZS 17 10.843 0.800 0.908 0.901 0.0621 0.119 DT 19 12.766 0.833 0.922 0.916 0.3156 0.096 XP 13 8.000 0.433 0.875 0.863 0.0000 * 0.505 HK 12 4.972 0.533 0.799 0.781 0.0000 * 0.332 BBW 12 4.700 0.533 0.787 0.761 0.0000* 0.323 YC275 SD 18 11.921 0.800 0.916 0.910 0.0000* 0.127 LYG 20 15.126 0.833 0.934 0.930 0.0000* 0.108 LS 21 13.043 0.867 0.923 0.918 0.1694 0.061 ZS 17 13.534 0.833 0.926 0.921 0.0593 0.100 DT 20 14.876 0.900 0.933 0.929 0.0226 0.035 XP 15 7.531 0.733 0.867 0.856 0.0000* 0.154 HK 18 13.235 1.000 0.924 0.919 0.0000 * -0.082 BBW 18 10.843 0.933 0.908 0.901 0.0000 * -0.028 YC339 SD 11 6.844 0.300 0.854 0.838 0.0000 * 0.649 LYG 12 7.895 0.600 0.873 0.862 0.0000* 0.313 LS 12 8.612 0.333 0.884 0.873 0.0000* 0.623 ZS 11 8.867 0.533 0.887 0.877 0.0000* 0.399 DT 13 7.759 0.467 0.871 0.858 0.0000 * 0.464 XP 11 8.333 0.633 0.880 0.868 0.0002 0.280 HK 11 6.475 0.267 0.846 0.829 0.0000* 0.685 BBW 12 7.792 0.400 0.872 0.859 0.0000* 0.541 YC353-1 SD 18 12.245 0.733 0.918 0.913 0.0230 0.201 LYG 19 13.534 0.733 0.926 0.921 0.0001 0.208 LS 21 14.754 0.833 0.932 0.928 0.0077 0.106 ZS 19 12.857 0.633 0.922 0.917 0.0001 0.313 DT 19 13.433 0.633 0.926 0.921 0.0000 * 0.316 XP 13 7.792 1.000 0.872 0.859 0.0110 -0.147 HK 14 7.895 0.767 0.873 0.861 0.0005 0.122 BBW 16 9.783 0.900 0.898 0.889 0.4368 -0.002 YC353-2 SD 11 6.642 0.467 0.849 0.833 0.0000 * 0.451 LYG 11 8.295 0.733 0.879 0.868 0.0089 0.166 LS 14 8.696 0.433 0.885 0.875 0.0000 * 0.510 ZS 18 10.345 0.600 0.903 0.897 0.0000* 0.336 DT 16 10.465 0.467 0.904 0.897 0.0000* 0.484 XP 11 6.569 0.733 0.848 0.831 0.0002 0.135 HK 11 6.923 0.667 0.856 0.841 0.0006 0.221 BBW 12 8.295 0.800 0.879 0.868 0.0938 0.090 YC459 SD 10 5.902 0.400 0.831 0.810 0.0000 * 0.518 LYG 9 3.766 0.367 0.734 0.698 0.0000 * 0.501 LS 12 5.085 0.500 0.803 0.787 0.0000* 0.378 ZS 7 3.358 0.267 0.702 0.654 0.0000* 0.620 DT 6 3.025 0.367 0.669 0.618 0.0000* 0.452 XP 10 6.000 1.000 0.833 0.813 0.0000* -0.200 HK 15 8.451 0.167 0.882 0.871 0.0000* 0.811 BBW 12 5.248 0.267 0.809 0.792 0.0000* 0.671 YC687 SD 14 10.588 0.233 0.906 0.898 0.0000 * 0.742 LYG 18 9.677 0.300 0.897 0.888 0.0000 * 0.665 LS 14 11.250 0.400 0.911 0.904 0.0000* 0.561 ZS 18 12.000 0.467 0.917 0.911 0.0000* 0.491 DT 18 11.250 0.567 0.911 0.905 0.0000* 0.378 XP 20 11.921 0.633 0.916 0.910 0.0000* 0.309 HK 6 4.327 0.100 0.769 0.733 0.0000* 0.870 BBW 9 5.696 0.200 0.824 0.803 0.0000* 0.757 YC705 SD 18 13.043 0.633 0.923 0.918 0.0000* 0.314 LYG 18 10.976 0.633 0.909 0.902 0.0000* 0.303 LS 19 13.433 0.633 0.926 0.921 0.0000* 0.316 ZS 18 13.235 0.733 0.924 0.919 0.0002 0.207 DT 17 14.876 0.800 0.933 0.929 0.1004 0.142 XP 20 14.063 0.633 0.929 0.924 0.0000 * 0.318 HK 20 14.400 0.700 0.931 0.926 0.0000 * 0.248 BBW 22 14.754 0.833 0.932 0.928 0.0067 0.106 YC731 SD 13 9.890 0.600 0.899 0.890 0.0000 * 0.333 LYG 13 9.626 0.200 0.896 0.887 0.0000 * 0.777 LS 13 8.531 0.433 0.883 0.872 0.0000* 0.509 ZS 15 10.112 0.533 0.901 0.893 0.0000* 0.408 DT 11 8.612 0.467 0.884 0.873 0.0000* 0.472 XP 10 5.625 0.400 0.822 0.801 0.0000* 0.514 HK 8 6.186 0.167 0.838 0.819 0.0000 * 0.801 BBW 13 8.295 0.267 0.879 0.867 0.0000* 0.697 YC742 SD 9 4.523 0.233 0.779 0.754 0.0000* 0.700 LYG 9 6.767 0.300 0.852 0.835 0.0000* 0.648 LS 10 5.751 0.633 0.826 0.804 0.0000* 0.233 ZS 12 6.792 0.700 0.853 0.836 0.0009 0.179 DT 9 5.471 0.700 0.817 0.792 0.0343 0.143 XP 9 3.956 0.167 0.747 0.717 0.0000 * 0.777 HK 12 6.792 0.533 0.853 0.837 0.0000* 0.375 BBW 12 6.250 0.433 0.840 0.821 0.0000* 0.484 YC754 SD 9 6.818 0.633 0.853 0.837 0.0007 0.258 LYG 12 6.383 0.300 0.843 0.826 0.0000 * 0.644 LS 11 5.202 0.567 0.808 0.788 0.0000* 0.298 ZS 10 5.263 0.500 0.810 0.788 0.0000* 0.383 DT 10 4.775 0.700 0.791 0.761 0.1399 0.115 XP 11 7.059 0.433 0.858 0.842 0.0000* 0.495 HK 16 10.526 0.633 0.905 0.898 0.0000* 0.300 BBW 12 8.451 0.700 0.882 0.871 0.0502 0.206 YC764 SD 21 15.652 0.767 0.936 0.932 0.0058 0.181 LYG 19 12.500 0.633 0.920 0.915 0.0000 * 0.312 LS 18 9.890 0.600 0.899 0.891 0.0000* 0.333 ZS 15 10.651 0.400 0.906 0.899 0.0000* 0.559 DT 18 13.043 0.667 0.923 0.918 0.0000* 0.278 XP 17 12.000 0.700 0.917 0.911 0.0000* 0.236 HK 14 8.036 0.533 0.876 0.864 0.0002 0.391 BBW 13 9.375 0.500 0.893 0.884 0.0000* 0.440 YC792 SD 14 8.451 0.533 0.882 0.872 0.0000* 0.395 LYG 12 7.115 0.400 0.859 0.844 0.0000* 0.535 LS 13 8.911 0.533 0.888 0.877 0.0000* 0.399 ZS 13 7.500 0.467 0.867 0.854 0.0000* 0.462 DT 15 9.626 0.633 0.896 0.888 0.0003 0.293 XP 13 8.036 0.267 0.876 0.864 0.0000* 0.695 HK 16 10.778 0.700 0.907 0.900 0.0011 0.228 BBW 16 11.538 0.700 0.913 0.907 0.0001 0.234 All locus SD 14.267 9.836 0.531 0.885 0.875 0.0038 0.405 LYG 14.667 9.702 0.533 0.883 0.872 0.0024 0.401 LS 15.200 10.123 0.593 0.889 0.879 0.0139 0.334 ZS 14.733 9.926 0.569 0.884 0.872 0.0165 0.361 DT 14.733 10.222 0.627 0.881 0.868 0.0441 0.290 XP 13.667 8.485 0.604 0.870 0.857 0.0057 0.309 HK 13.000 8.340 0.504 0.867 0.854 0.0004 0.426w BBW 13.467 8.583 0.547 0.873 0.860 0.0430 0.379 A = the number of alleles per locus, Ae = the number of effective alleles per locus, PIC = polymorphism information content, Ho = observed heterozygosity, He = expected heterozygosity, FIS = the inbreeding coefficient (*, significantly value of HWE greater than zero after sequential Bonferroni corrections). ). Within sampling locations, the mean expected heterozygosities (He) were consistently higher than the observed one (Ho) across all loci, which revealed a deficit of heterozygosity among the samples.

Population structure

Significant genetic heterozygosity among the eight populations was indicated by AMOVA analysis. The results showed that 4.34% of total genetic variation came from among population variation, while the within population variation explained 95.66% of total variation. Genetic differentiation between populations was analyzed using FST. The overall FST value over all locations and loci was statistically different from zero (Fixation Index FST=0.0434, p<0.001) (Table 2). Pairwise FST comparing population pairs ranged from 0.022 (DT and ZS) to 0.074 (HK and XP) (Table 3). The highest genetic differentiation between populations using FST was between the populations HK and XP, while the lowest differentiation was between DT and ZS (Table 3). The results of FST indicated that there was low but statistically significant genetic differentiation among the populations.

Table 2
AMOVA analysis of eight populations of P. argenteus.
Table 3
Estimates of pairwise FST values (below diagonal) and Nei's Genetic Distance (above diagonal) between eight populations of P. argenteus detected by 15 microsatellites.

UPGMA phylogenetic trees (Figure 2) were constructed on the basis of Nei's genetic distance matrix (Table 3). Eight populations were divided into two main clusters: HK and BBW populations formed Cluster I; ClusterⅡincludes the remaining six populations. Cluster II is consisted of three subgroups, i.e., subgroup 1 includes XP, subgroup 2 includes LS, and subgroup 3 includes two SD, LYG, ZS, and DT (Figure 3). Mantel Test showed that there are significant linear correlation between geographic distances and genetic distances with R2=0.8012 (data not shown), which could imply isolation by distance. Furthermore, the PCA analysis also showed the HK and BBW populations to be genetically distinct from the other six locations (Figure 3). These results are consistent with the FST and Nei's distance tests.

Figure 2
Unweighted Pair-group Method with Arithmetic Means tree (UPGMA) of eight populations of P. argenteus based on Nei's genetic distance.

Figure 3
Principal component analysis (PCA) of eight populations of P. argenteus.

Demographic Bottleneck

Analysis of recent population declines of P. argenteus was detected using the Wilcoxon signed-rank test in BOTTLENECK under two models of microsatellite evolution (SMM and TPM)(Table 4). Excepted TPM (90%) for SD and DT, the probability values of the bottleneck test all above 0.05 (Table 4), suggesting no significant excess of heterozygosity in most populations. It indicated that there was no genetic bottleneck in most of the eight populations due to mutation-drift equilibrium. In addition, the mode-shift test showed that all populations were in normal L-shaped pattern of the allele frequency distributions (Table 4), revealing the lack of population declines in the recent history of P. argenteus.

Table 4
p-values of bottleneck tests for detecting the recent population declines of P. argenteus using stepwise mutation model (SMM), two phased mutation model (TPM), and mode shift indicator.

DISCUSSION

In this study, we examined the genetic diversity and population structure of eight wild populations of P. argenteus using 15 highly polymorphic microsatellites. We observed low but significant genetic differences in the spatial distribution of P. argenteus along the coast of China. The results suggested a high level of population genetic diversity of P. argenteus (A:13.000-15.200, Ho:0.504-0.627, He: 0.867-0.889, and PIC:0.854-0.879), which is in line with the previous studies that showed a high level of genetic diversity in P. argenteus using RAPD, AFLP and mtDNA (Meng et al., 2009MENG, Y. Y., ZHANG, L. Z., ZHAO, F., SHI, Z. H. & ZHUANG, P. 2009. Preliminary study on the genetic diversity of four geographic populations of silver pomfret (Pampus argenteus). Marine Fisheries, 31, 48-52. [In Chinese]; Zhao et al., 2011aZHAO, F., DONG, Y., ZHUANG, P., ZHANG, T., ZHANG, L. Z. & SHI, Z. H. 2011a. Genetic diversity of silver pomfret (Pampus argenteus) in the Southern Yellow and East China Seas. Biochemical Systematics and Ecology, 39, 145-150.; Peng et al., 2009aPENG, S. M., SHI, Z. H., HOU, J. L., WANG, W., ZHAO, F. & ZHANG, H. 2009a. Genetic diversity of silver pomfret (Pampus argenteus) populations from the China Sea based on mitochondrial DNA control region sequences. Biochemical Systematics and Ecology, 37, 626-632.; Wu et al., 2012WU, R. X., LIANG, X. H. & ZHUANG, Z. M. 2012. Mitochondrial COI sequance variation of silver pomfret (Pampus argenteus) from Chinese coastal waters. Acta Zootaxonomica Sinica, 37, 480-488. [In Chinese]). Genetic diversity is not only the consequence of evolution, but also represented the evolution potential of animals. In order to be fit for survival, animals accumulated more genetic diversity to ensure their increase of the fitness for many kinds of environmental pressures (Liu et al., 2010LIU, W. X., LIU, W. H., WU, J., GAO, A. N. & LI, L. H. 2010. Analysis of genetic diversity in natural populations of Psathyrostachys huashanica Keng using microsatellite (SSR) markers. Journal of Integrative Agriculture, 9, 463-471.). P. argenteus may use a relative high genetic diversity to adopt its rigorous habitats during its evolution.

The amount of effective alleles (Ae) was obviously less than that of the observed alleles (A) (Table Sup. Supplementary Table Table Sup Statistics for genetic variation at 15 microsatellite loci in eight populations of P. argenteus. Locus Population Parameters A Ae Ho He PIC PHWE Fis YC79 SD 17 13.333 0.567 0.925 0.920 0.0000 * 0.387 LYG 14 9.524 0.767 0.895 0.886 0.0019 0.143 LS 17 13.636 0.767 0.927 0.922 0.0040 0.173 ZS 16 12.950 0.667 0.923 0.917 0.0004 0.278 DT 16 12.245 0.533 0.918 0.913 0.0000 * 0.419 XP 16 10.169 0.767 0.902 0.894 0.0526 0.150 HK 10 7.531 0.433 0.867 0.853 0.0000 * 0.500 BBW 12 9.278 0.433 0.892 0.882 0.0000 * 0.514 YC90 SD 15 12.500 0.333 0.920 0.914 0.0000 * 0.638 LYG 15 9.836 0.333 0.898 0.890 0.0000* 0.629 LS 14 11.613 0.533 0.914 0.907 0.0000* 0.416 ZS 15 10.588 0.400 0.906 0.898 0.0000* 0.558 DT 14 11.111 0.667 0.910 0.903 0.0025 0.267 XP 16 10.227 0.533 0.902 0.894 0.0000 * 0.409 HK 12 8.571 0.367 0.883 0.872 0.0000* 0.585 BBW 11 8.451 0.300 0.882 0.870 0.0000* 0.660 YC140 SD 16 9.184 0.733 0.891 0.882 0.0008 0.177 LYG 19 14.516 0.867 0.931 0.927 0.0042 0.069 LS 19 13.433 0.833 0.926 0.921 0.0001 0.100 ZS 17 10.843 0.800 0.908 0.901 0.0621 0.119 DT 19 12.766 0.833 0.922 0.916 0.3156 0.096 XP 13 8.000 0.433 0.875 0.863 0.0000 * 0.505 HK 12 4.972 0.533 0.799 0.781 0.0000 * 0.332 BBW 12 4.700 0.533 0.787 0.761 0.0000* 0.323 YC275 SD 18 11.921 0.800 0.916 0.910 0.0000* 0.127 LYG 20 15.126 0.833 0.934 0.930 0.0000* 0.108 LS 21 13.043 0.867 0.923 0.918 0.1694 0.061 ZS 17 13.534 0.833 0.926 0.921 0.0593 0.100 DT 20 14.876 0.900 0.933 0.929 0.0226 0.035 XP 15 7.531 0.733 0.867 0.856 0.0000* 0.154 HK 18 13.235 1.000 0.924 0.919 0.0000 * -0.082 BBW 18 10.843 0.933 0.908 0.901 0.0000 * -0.028 YC339 SD 11 6.844 0.300 0.854 0.838 0.0000 * 0.649 LYG 12 7.895 0.600 0.873 0.862 0.0000* 0.313 LS 12 8.612 0.333 0.884 0.873 0.0000* 0.623 ZS 11 8.867 0.533 0.887 0.877 0.0000* 0.399 DT 13 7.759 0.467 0.871 0.858 0.0000 * 0.464 XP 11 8.333 0.633 0.880 0.868 0.0002 0.280 HK 11 6.475 0.267 0.846 0.829 0.0000* 0.685 BBW 12 7.792 0.400 0.872 0.859 0.0000* 0.541 YC353-1 SD 18 12.245 0.733 0.918 0.913 0.0230 0.201 LYG 19 13.534 0.733 0.926 0.921 0.0001 0.208 LS 21 14.754 0.833 0.932 0.928 0.0077 0.106 ZS 19 12.857 0.633 0.922 0.917 0.0001 0.313 DT 19 13.433 0.633 0.926 0.921 0.0000 * 0.316 XP 13 7.792 1.000 0.872 0.859 0.0110 -0.147 HK 14 7.895 0.767 0.873 0.861 0.0005 0.122 BBW 16 9.783 0.900 0.898 0.889 0.4368 -0.002 YC353-2 SD 11 6.642 0.467 0.849 0.833 0.0000 * 0.451 LYG 11 8.295 0.733 0.879 0.868 0.0089 0.166 LS 14 8.696 0.433 0.885 0.875 0.0000 * 0.510 ZS 18 10.345 0.600 0.903 0.897 0.0000* 0.336 DT 16 10.465 0.467 0.904 0.897 0.0000* 0.484 XP 11 6.569 0.733 0.848 0.831 0.0002 0.135 HK 11 6.923 0.667 0.856 0.841 0.0006 0.221 BBW 12 8.295 0.800 0.879 0.868 0.0938 0.090 YC459 SD 10 5.902 0.400 0.831 0.810 0.0000 * 0.518 LYG 9 3.766 0.367 0.734 0.698 0.0000 * 0.501 LS 12 5.085 0.500 0.803 0.787 0.0000* 0.378 ZS 7 3.358 0.267 0.702 0.654 0.0000* 0.620 DT 6 3.025 0.367 0.669 0.618 0.0000* 0.452 XP 10 6.000 1.000 0.833 0.813 0.0000* -0.200 HK 15 8.451 0.167 0.882 0.871 0.0000* 0.811 BBW 12 5.248 0.267 0.809 0.792 0.0000* 0.671 YC687 SD 14 10.588 0.233 0.906 0.898 0.0000 * 0.742 LYG 18 9.677 0.300 0.897 0.888 0.0000 * 0.665 LS 14 11.250 0.400 0.911 0.904 0.0000* 0.561 ZS 18 12.000 0.467 0.917 0.911 0.0000* 0.491 DT 18 11.250 0.567 0.911 0.905 0.0000* 0.378 XP 20 11.921 0.633 0.916 0.910 0.0000* 0.309 HK 6 4.327 0.100 0.769 0.733 0.0000* 0.870 BBW 9 5.696 0.200 0.824 0.803 0.0000* 0.757 YC705 SD 18 13.043 0.633 0.923 0.918 0.0000* 0.314 LYG 18 10.976 0.633 0.909 0.902 0.0000* 0.303 LS 19 13.433 0.633 0.926 0.921 0.0000* 0.316 ZS 18 13.235 0.733 0.924 0.919 0.0002 0.207 DT 17 14.876 0.800 0.933 0.929 0.1004 0.142 XP 20 14.063 0.633 0.929 0.924 0.0000 * 0.318 HK 20 14.400 0.700 0.931 0.926 0.0000 * 0.248 BBW 22 14.754 0.833 0.932 0.928 0.0067 0.106 YC731 SD 13 9.890 0.600 0.899 0.890 0.0000 * 0.333 LYG 13 9.626 0.200 0.896 0.887 0.0000 * 0.777 LS 13 8.531 0.433 0.883 0.872 0.0000* 0.509 ZS 15 10.112 0.533 0.901 0.893 0.0000* 0.408 DT 11 8.612 0.467 0.884 0.873 0.0000* 0.472 XP 10 5.625 0.400 0.822 0.801 0.0000* 0.514 HK 8 6.186 0.167 0.838 0.819 0.0000 * 0.801 BBW 13 8.295 0.267 0.879 0.867 0.0000* 0.697 YC742 SD 9 4.523 0.233 0.779 0.754 0.0000* 0.700 LYG 9 6.767 0.300 0.852 0.835 0.0000* 0.648 LS 10 5.751 0.633 0.826 0.804 0.0000* 0.233 ZS 12 6.792 0.700 0.853 0.836 0.0009 0.179 DT 9 5.471 0.700 0.817 0.792 0.0343 0.143 XP 9 3.956 0.167 0.747 0.717 0.0000 * 0.777 HK 12 6.792 0.533 0.853 0.837 0.0000* 0.375 BBW 12 6.250 0.433 0.840 0.821 0.0000* 0.484 YC754 SD 9 6.818 0.633 0.853 0.837 0.0007 0.258 LYG 12 6.383 0.300 0.843 0.826 0.0000 * 0.644 LS 11 5.202 0.567 0.808 0.788 0.0000* 0.298 ZS 10 5.263 0.500 0.810 0.788 0.0000* 0.383 DT 10 4.775 0.700 0.791 0.761 0.1399 0.115 XP 11 7.059 0.433 0.858 0.842 0.0000* 0.495 HK 16 10.526 0.633 0.905 0.898 0.0000* 0.300 BBW 12 8.451 0.700 0.882 0.871 0.0502 0.206 YC764 SD 21 15.652 0.767 0.936 0.932 0.0058 0.181 LYG 19 12.500 0.633 0.920 0.915 0.0000 * 0.312 LS 18 9.890 0.600 0.899 0.891 0.0000* 0.333 ZS 15 10.651 0.400 0.906 0.899 0.0000* 0.559 DT 18 13.043 0.667 0.923 0.918 0.0000* 0.278 XP 17 12.000 0.700 0.917 0.911 0.0000* 0.236 HK 14 8.036 0.533 0.876 0.864 0.0002 0.391 BBW 13 9.375 0.500 0.893 0.884 0.0000* 0.440 YC792 SD 14 8.451 0.533 0.882 0.872 0.0000* 0.395 LYG 12 7.115 0.400 0.859 0.844 0.0000* 0.535 LS 13 8.911 0.533 0.888 0.877 0.0000* 0.399 ZS 13 7.500 0.467 0.867 0.854 0.0000* 0.462 DT 15 9.626 0.633 0.896 0.888 0.0003 0.293 XP 13 8.036 0.267 0.876 0.864 0.0000* 0.695 HK 16 10.778 0.700 0.907 0.900 0.0011 0.228 BBW 16 11.538 0.700 0.913 0.907 0.0001 0.234 All locus SD 14.267 9.836 0.531 0.885 0.875 0.0038 0.405 LYG 14.667 9.702 0.533 0.883 0.872 0.0024 0.401 LS 15.200 10.123 0.593 0.889 0.879 0.0139 0.334 ZS 14.733 9.926 0.569 0.884 0.872 0.0165 0.361 DT 14.733 10.222 0.627 0.881 0.868 0.0441 0.290 XP 13.667 8.485 0.604 0.870 0.857 0.0057 0.309 HK 13.000 8.340 0.504 0.867 0.854 0.0004 0.426w BBW 13.467 8.583 0.547 0.873 0.860 0.0430 0.379 A = the number of alleles per locus, Ae = the number of effective alleles per locus, PIC = polymorphism information content, Ho = observed heterozygosity, He = expected heterozygosity, FIS = the inbreeding coefficient (*, significantly value of HWE greater than zero after sequential Bonferroni corrections). ), indicating that some alleles were lost between the populations studied in this study. The amount of alleles is very important to maintain populations because it provides the necessary spectrum of genotypes for adaptive response to changing environments (Thai et al., 2007THAI, B. T., BURRIDGE, C. P. & AUSTIN, C. M. 2007. Genetic diversity of common carp (Cyprinus carpio L.) in Vietnam using four microsatellite loci. Aquaculture, 269, 174-186.). The loss of genetic diversity will prevent future improvements via selection of the species to a certain extent. The most likely explanation for the loss of alleles may be that the wild population was under stress from overfishing and deterioration in the environment resulting in less recruitment (Alam and Islam, 2005ALAM, S. & ISLAM, S. 2005. Population genetic structure of Catla catla (Hamilton) revealed by microsatellite DNA markers. Aquaculture, 246, 151-160.). In order to prevent the alleles from losing and to conserve the genetic resource, we could strengthen the conservation and supervision of wild resources and forbid overfishing in the natural waters.

Generally, marine species are capable of migration over long distances, showing little or no genetic differentiation in geographic scales because of long distance pelagic dispersal potential during planktonic egg, larval, or adult history stages coupled with an absence of physical barriers to movement between ocean basins or adjacent continental margins (Hewitt, 2000HEWITT, G. M. 2000. The genetic legacy of the Quaternary ice ages. Nature, 405, 907-913.). The small but highly significant values of pairwise FST in the present study indicated that the P. argenteus have genetic differentiation among populations, and more than 95.66% of the total genetic variation was among individuals within populations (Table 2). UPGMA and PCA analysis indicated that the population of eight P. argenteus can divided into two major groups: one group including populations of P. argenteus in the South China Sea (SCS) and the other group consisting populations of P. argenteus in the Yellow Sea (YS) and the East China Sea (ECS). Earlier studies using RAPD and mtDNA (Meng et al., 2009MENG, Y. Y., ZHANG, L. Z., ZHAO, F., SHI, Z. H. & ZHUANG, P. 2009. Preliminary study on the genetic diversity of four geographic populations of silver pomfret (Pampus argenteus). Marine Fisheries, 31, 48-52. [In Chinese]; Peng et al., 2009PENG, S. M., SHI, Z. H., HOU, J. L., WANG, W., ZHAO, F. & ZHANG, H. 2009a. Genetic diversity of silver pomfret (Pampus argenteus) populations from the China Sea based on mitochondrial DNA control region sequences. Biochemical Systematics and Ecology, 37, 626-632.) did support the idea that the populations from the South China Sea are genetically different from other populations. In all, these results revealed that there are different isolation patterns between two major groups and significant population differentiation throughout the examined range of sampled locations. Populations of P. argenteus seem to show high levels of gene flow between ECS and YS groups. A complex system of surface currents is likely the main factor influencing gene flow. The China Coastal Current and Yellow Sea Warm Current, including outflow of water from the Yellow Sea to the East China Sea along the China coast and inflow from the East China Sea to the Yellow Sea along the west coast of Korea (Li et al., 2000LI, N. S., ZHAO, S. L. & WASILIEV, B. 2000. Geology of marginal sea in the Northwest Pacific, Harbin, Heilongjiang Education Press. [In Chinese]), respectively, could contribute to mixing of YS and ECS groups. The gene flow between populations from the South China Sea and other populations may be limited by some factors such as oceanographic characteristics and life history.

Zhao et al. (2011b)ZHAO, F., ZHUANG, P., ZHANG, L. Z., SHI, Z. H. 2011b. Morphological variation of Pampus argenteus among five samples near the coastal area of the Bohai Sea, Huanghai Sea and East China Sea. Acta Oceanologica Sinica, 33, 104-110. indicates that LYG and ZS samples have close relationship. However, our study results show that the normalized Euclidean distance between ZS and DT samples was shorter than all other pairwise distances. In general, morphological differences of P. argenteus among Chinese coastal waters can be discerned by multivariate morphometrics methods. Our study with microsatellite as marker showed significant genetic differentiation in P. argenteus, which were to some extend different from the results based on mitochondrial DNA gene sequences (Peng et al., 2009bPENG, S. M., SHI, Z. H., HOU, J. L., ZHANG, H. & ZHAO, F. 2009b. Genetic diversity of three wild silver pomfret (Pampus argenteus) populations based on COI gene sequences. Journal of Shanghai Ocean University, 18, 398-402.; Wu et al., 2012WU, R. X., LIANG, X. H. & ZHUANG, Z. M. 2012. Mitochondrial COI sequance variation of silver pomfret (Pampus argenteus) from Chinese coastal waters. Acta Zootaxonomica Sinica, 37, 480-488. [In Chinese]). The reasons leading to this divergence may include intrinsic variability of the population, sample size, spatial replication, and the number and characteristics of the marker loci used (Curley and Gillings, 2009CURLEY, B. G. & GILLINGS, M. R. 2009. Population connectivity in the temperate damselfish Parma microlepis: analysis of genetic structure across multiple spatial scales. Marine Biology, 156, 381-393.). More samples should be collected from all over Chinese coastal waters including Bohai Sea, Yellow Sea, East China Sea and South China Sea to allow for a more comprehensive picture of genetic variation of this species.

ACKNOWLEDGEMENTS

This work was supported by Central Public-interest Scientific Institution Basal Research Fund, ECSFR, CAFS (No.2012M09) and Science and Technology Commission of Shanghai Municipality (Shanghai Natural Science Foundation No. 19ZR1470100).

REFERENCES

  • ALAM, S. & ISLAM, S. 2005. Population genetic structure of Catla catla (Hamilton) revealed by microsatellite DNA markers. Aquaculture, 246, 151-160.
  • CORNUET, J. M. & LUIKART, G. 1996. Description and power analysis of two tests for detecting recent population bottlenecks from allele frequency data. Genetics, 144, 2001-2014.
  • CURLEY, B. G. & GILLINGS, M. R. 2009. Population connectivity in the temperate damselfish Parma microlepis: analysis of genetic structure across multiple spatial scales. Marine Biology, 156, 381-393.
  • DAVIS, P. & WHEELER, A. 1985. The occurrence of Pampus argenteus (Euphrasen, 1788), (Osteichthyes, Perciformes, Stromateoidei, Stromateidae) in the North Sea. Journal of Fish Biology, 26, 105-109.
  • EXCOFFIER, L., LAVAL, G. & SCHNEIDER, S. 2005. Arlequin version 3.0: An integrated software package for population genetics data analysis. Evolutionary Bioinformatics, 1, 47-50.
  • GOLDSTEIN, D. B. & SCHLOTTERER, C. 1999. Microsatellites: Evolution and Applications, Oxford, Oxford University Press.
  • HERWERDEN, L. V., BLAIR, D. & AGATSUMA, T. 1999. Genetic diversity in parthenogenetic triploid Paragonimus westermani International Journal for Parasitology, 29, 1477-1482.
  • HEWITT, G. M. 2000. The genetic legacy of the Quaternary ice ages. Nature, 405, 907-913.
  • JIN, X., ZHAO, X., MENG, T. & CUI, Y. M. 2005. Biology Resources and Habitat Environment in Yellow and Bohai Seas, Beijing, Science Press. [In Chinese]
  • KIPER, I. E., BLOOMER, P., BORSA, P. & HOAREAU, T. B. 2018. Characterization of genome-wide microsatellite markers in rabbitfishes, an important resource for artisanal fisheries in the Indo-West Pacific. Molecular Biology Reports, 45, 19-25.
  • LI, N. S., ZHAO, S. L. & WASILIEV, B. 2000. Geology of marginal sea in the Northwest Pacific, Harbin, Heilongjiang Education Press. [In Chinese]
  • LIU, J., LI, C. S. & LI, X. S. 2002. Phylogeny and biogeography of Chinese pomfret fishes (Pisces: Stromateidae). Studia Marina Sinica, 44, 235-239. [In Chinese]
  • LIU, Z. J. & CORDES, J. F. 2004. DNA marker technologies and their applications in aquaculture genetics. Aquaculture, 238, 1-137.
  • LIU, W. X., LIU, W. H., WU, J., GAO, A. N. & LI, L. H. 2010. Analysis of genetic diversity in natural populations of Psathyrostachys huashanica Keng using microsatellite (SSR) markers. Journal of Integrative Agriculture, 9, 463-471.
  • LUIKART, G. & CORNUET, J. M. 1998. Empirical Evaluation of a Test for Identifying Recently Bottlenecked Populations from Allele Frequency Data. Conservation Biology, 12, 228-237.
  • MARSHALL, T. C., SLATE, J., KRUUK, L. E. B. & PEMBERTON, J. M. 1998. Statistical confidence for likelihood-based paternity inference in natural populations. Molecular Ecology, 17, 639-655.
  • MENG, Y. Y., ZHANG, L. Z., ZHAO, F., SHI, Z. H. & ZHUANG, P. 2009. Preliminary study on the genetic diversity of four geographic populations of silver pomfret (Pampus argenteus). Marine Fisheries, 31, 48-52. [In Chinese]
  • MUTHS, D., GREWE, P., JEAN, C. & BOURJEA, J. 2009. Genetic population structure of the Swordfish (Xiphias gladius) in the southwest Indian Ocean: Sex-biased differentiation, congruency between markers and its incidence in a way of stock assessment. Fisheries Research, 97, 263-269.
  • NEI, M. 1978. Estimation of average heterozygosity and genetic distance from a small number of individuals. Genetics, 89, 583-590.
  • PALUMBI, S. R. 2003. Population genetics, demographic connectivity, and the design of marine reserves. Ecological Applications, 13, 146-158.
  • PEAKALL, R. & SMOUSE, P. E. 2006. GENALEX 6: genetic analysis in Excel. Population genetic software for teaching and research. Molecular Ecology Resources, 6, 288-295.
  • PENG, S. M., SHI, Z. H., HOU, J. L., WANG, W., ZHAO, F. & ZHANG, H. 2009a. Genetic diversity of silver pomfret (Pampus argenteus) populations from the China Sea based on mitochondrial DNA control region sequences. Biochemical Systematics and Ecology, 37, 626-632.
  • PENG, S. M., SHI, Z. H., HOU, J. L., ZHANG, H. & ZHAO, F. 2009b. Genetic diversity of three wild silver pomfret (Pampus argenteus) populations based on COI gene sequences. Journal of Shanghai Ocean University, 18, 398-402.
  • PENG, S. M., SHI, Z. H. & HOU, J. L. 2010. Comparative analysis on the genetic diversity of cultured and wild silver pomfret populations based on mtD-loop and COI gene. Journal of Fisheries of China, 34, 19-25. [In Chinese]
  • PIRY, S., LUIKART, G. & CORNUET, J. M. 1999. BOTTLENECK: a computer program for detecting recent reductions in the effective population size using allele frequency data. Journal of Heredity, 90, 502-503.
  • RAYMOND, M. & ROUSSET, F. 1995. Genepop (version-1.2): Population genetics software for exact tests and ecumenicism. Journal of Heredity, 86, 248-249.
  • RICE, W. R. 1989. Analyzing tables of statistical tests. Evolution, 43, 223-225.
  • SAMBROOK, J., FRITSCH, E. F. & MANIATIS, T. 1989. Molecular cloning: a laboratory manual, New York, Cold Spring Harbor Laboratory Press.
  • SHRIVER, M. D., JIN, L., CHAKRABORTY, R. & BOERWINKLE, E. 1993. Vntr Allele Frequency Distributions under the Stepwise Mutation Model: A Computer Simulation Approach. Genetics, 134, 983-993.
  • TAMURA, K., PETERSON, D., PETERSON, N., STECHER, G., NEI, M. & KUMAR, S. 2011. MEGA5: Molecular Evolutionary Genetics Analysis Using Maximum Likelihood, Evolutionary Distance, and Maximum Parsimony Methods. Molecular Biology and Evolution, 28, 2731-2739.
  • THAI, B. T., BURRIDGE, C. P. & AUSTIN, C. M. 2007. Genetic diversity of common carp (Cyprinus carpio L.) in Vietnam using four microsatellite loci. Aquaculture, 269, 174-186.
  • VALDES, A. M., SLATKIN, M. & FREIMER, N. B. 1993. Allele frequencies at microsatellite loci: the stepwise mutation model revisited. Genetics, 133, 737-749.
  • VARGAS-CARO, C., BUSTAMANTE, C., BENNETT, M. B. & OVENDEN, J. R. 2017. Towards sustainable fishery management for skates in South America: The genetic population structure of Zearaja chilensis and Dipturus trachyderma (Chondrichthyes, Rajiformes) in the south-east Pacific Ocean. PLoS One, 12, e0172255.
  • WU, R. X., LIANG, X. H. & ZHUANG, Z. M. 2012. Mitochondrial COI sequance variation of silver pomfret (Pampus argenteus) from Chinese coastal waters. Acta Zootaxonomica Sinica, 37, 480-488. [In Chinese]
  • XU, G. P., LI, X. G., ZHONG, X. M., LIU, P. T. & TANG, J. H. 2008. Research on genetic diversity of Pampus argentells population in Jiangsu Province by isozyme and ISSR. Jiangsu Agricultural Sciences, 36, 80-82. [In Chinese]
  • ZHANG, Q. H., CHENG, J. H., XU, H. X. & ZHENG, Y. J. 2007. Fishery Resources and Its Sustainable Utilization in the East China Sea Region, Shanghai, Fudan University Press. [In Chinese]
  • ZHAO, F., DONG, Y., ZHUANG, P., ZHANG, T., ZHANG, L. Z. & SHI, Z. H. 2011a. Genetic diversity of silver pomfret (Pampus argenteus) in the Southern Yellow and East China Seas. Biochemical Systematics and Ecology, 39, 145-150.
  • ZHAO, F., ZHUANG, P., ZHANG, L. Z., SHI, Z. H. 2011b. Morphological variation of Pampus argenteus among five samples near the coastal area of the Bohai Sea, Huanghai Sea and East China Sea. Acta Oceanologica Sinica, 33, 104-110.

Supplementary Table

Table Sup
Statistics for genetic variation at 15 microsatellite loci in eight populations of P. argenteus.

Edited by

Editor: June Ferraz Dias

Publication Dates

  • Publication in this collection
    02 Dec 2019
  • Date of issue
    2019

History

  • Received
    29 Jan 2019
  • Accepted
    02 Oct 2019
Universidade de São Paulo, Instituto Oceanográfico Praça do Oceanográfico, 191 , 05508-120 Cidade Universitária, São Paulo - SP - Brasil, Tel.: (55 11) 3091-6501, Fax: (55 11) 3032-3092 - São Paulo - SP - Brazil
E-mail: io@usp.br