Research Article |
Corresponding author: Tian-Xiang Gao ( gaotianxiang0611@163.com ) Academic editor: Sven Kullander
© 2018 Yuan Li, Long-Shan Lin, Tian-Xiang Gao.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Li Y, Lin L-S, Gao T-X (2018) Genetic signatures of polymorphic microsatellite loci in the Ambiguous silver pomfret, Pampus argenteus (Teleostei, Stromateidae). ZooKeys 810: 139-151. https://doi.org/10.3897/zookeys.805.25602
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Pampus argenteus is a broadly exploited pelagic fish species, commonly misidentified as Pampus echinogaster. Genetic variation and population structure in Pampus argenteus was studied based on seven microsatellite loci. The observed high average allele number, heterozygosity values, and polymorphism information content of P. argenteus suggested high genetic diversity. No population genetic differentiation was detected based on the results of pairwise Fst, three-dimensional factorial correspondence analysis (3D-FCA) and STRUCTURE analysis, which implied continuous gene flow. Wilcoxon signed rank tests did not indicate significant heterozygosity excess, and recent genetic bottleneck events were not detected. Coupled with previous mitochondrial DNA results, the findings presented here indicate that high gene flow characterizes the current phylogeographic pattern of the species.
Genetic diversity, genetic structure, microsatellite DNA, population genetics
Species of the genus Pampus Bonaparte, 1834, are mainly distributed in the Indo-West Pacific Ocean and have a rich landing yield in Kuwait, Iran, India, Malaysia, Thailand, China, Korea and Japan (
Pampus argenteus is a multiple batch spawner with indeterminate fecundity, and spawning starts in mid-May and continues until early October. Transformation from the larval to juvenile stage occurs at 40 days after hatching (
Microsatellites (simple sequence repeats, SSRs) are tandemly repeated motifs of 1–6 bases characterized by a high degree of length polymorphism (
A total of 119 specimens of P. argenteus was collected from the coastal waters of Kuwait, Pakistan, and China from 2010 until 2014 (Figure
Summary statistics for the variability seven polymorphic microsatellite loci in six P. argenteus populations.
Location | Number of individuals | Date | Locus | Average | |||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Parameters | Par 03 | Par 08 | Par 20 | Par 05 | Par 12 | Par 18 | Par 17 | ||||
Sonmiani Bay (SO) | 21 | 2010.12 | A | 19 | 12 | 10 | 10 | 15 | 10 | 13 | 12.71 |
RS | 13.360 | 10.000 | 6.041 | 5.478 | 9.412 | 5.634 | 10.618 | 8.649 | |||
HO | 0.429 | 0.750 | 0.810 | 0.476 | 0.600 | 0.600 | 0.789 | 0.636 | |||
HE | 0.948 | 0.923 | 0.855 | 0.837 | 0.917 | 0.844 | 0.930 | 0.893 | |||
PIC | 0.920 | 0.892 | 0.815 | 0.798 | 0.885 | 0.800 | 0.898 | 0.858 | |||
Ormara (OR) | 28 | 2010.12 | A | 18 | 15 | 12 | 15 | 16 | 15 | 16 | 15.29 |
RS | 11.130 | 7.396 | 8.522 | 10.453 | 10.721 | 7.649 | 10.962 | 9.548 | |||
HO | 0.333 | 0.679 | 0.786 | 0.857 | 0.889 | 0.464 | 0.778 | 0.684 | |||
HE | 0.927 | 0.881 | 0.899 | 0.921 | 0.924 | 0.885 | 0.926 | 0.909 | |||
PIC | 0.904 | 0.852 | 0.872 | 0.897 | 0.899 | 0.856 | 0.902 | 0.883 | |||
Pasni (PS) | 12 | 2010.12 | A | 11 | 9 | 8 | 10 | 14 | 9 | 13 | 10.57 |
RS | 9.000 | 5.647 | 5.647 | 6.400 | 12.522 | 6.698 | 8.471 | 7.769 | |||
HO | 0.250 | 0.667 | 1.000 | 0.750 | 0.833 | 0.333 | 0.667 | 0.643 | |||
HE | 0.928 | 0.859 | 0.859 | 0.880 | 0.960 | 0.888 | 0.920 | 0.899 | |||
PIC | 0.879 | 0.805 | 0.800 | 0.828 | 0.914 | 0.833 | 0.871 | 0.847 | |||
Kuwait (KW) | 23 | 2011.09 | A | 20 | 10 | 11 | 13 | 14 | 15 | 13 | 13.71 |
RS | 13.444 | 3.421 | 6.782 | 6.541 | 9.584 | 8.015 | 8.015 | 7.972 | |||
HO | 0.727 | 0.455 | 0.957 | 0.636 | 0.773 | 0.478 | 0.565 | 0.656 | |||
HE | 0.947 | 0.724 | 0.871 | 0.867 | 0.916 | 0.895 | 0.895 | 0.874 | |||
PIC | 0.921 | 0.685 | 0.838 | 0.834 | 0.887 | 0.864 | 0.864 | 0.842 | |||
Taiwan (TW) | 11 | 2012.09 | A | 14 | 10 | 7 | 11 | 8 | 9 | 11 | 10.00 |
RS | 12.500 | 5.500 | 4.172 | 9.680 | 7.118 | 7.333 | 7.118 | 7.632 | |||
HO | 0.500 | 0.727 | 0.636 | 0.727 | 0.455 | 0.545 | 0.545 | 0.591 | |||
HE | 0.968 | 0.857 | 0.797 | 0.939 | 0.900 | 0.905 | 0.900 | 0.895 | |||
PIC | 0.914 | 0.798 | 0.732 | 0.887 | 0.843 | 0.848 | 0.845 | 0.838 | |||
Xiamen (XM) | 24 | 2014.04 | A | 20 | 16 | 13 | 11 | 16 | 11 | 15 | 14.57 |
RS | 15.781 | 11.755 | 8.229 | 6.227 | 8.417 | 5.409 | 9.600 | 9.345 | |||
HO | 0.417 | 0.875 | 0.750 | 0.708 | 0.682 | 0.667 | 0.708 | 0.687 | |||
HE | 0.957 | 0.934 | 0.897 | 0.857 | 0.902 | 0.832 | 0.915 | 0.899 | |||
PIC | 0.933 | 0.909 | 0.868 | 0.820 | 0.872 | 0.793 | 0.887 | 0.869 |
Genomic DNA was isolated from muscle tissue by proteinase K digestion and extracted using the DNeasy Blood and Tissue Kit (Qiagen, Valencia, CA, USA). Seven microsatellite loci developed by
The number of alleles (NA), observed heterozygosity (HO) and expected heterozygosity (HE) were estimated using POPGENE 1.32 (
FSTAT 2.9.3 (
The possibility of a cryptic population structure of P. argenteus was checked using STRUCTURE (
The Bottleneck 1.2.02 program (
A total of 150 alleles were detected by seven microsatellite loci for six populations, with a range of 14 (Par 20) to 31 (Par 03) (Table
The values of pairwise Fst showed low genetic differentiation among P. argenteus populations ranging from 0.001 to 0.026. Most P-values were not significant after sequential Bonferroni procedures except those between Kuwait (KW) and the other populations (Xiamen and Sonmiani Bay) (Table
Pairwise Fst (below diagonal) and (δμ)2 genetic distance (above diagonal) among P. argenteus populations.
SO | OR | PS | KW | TW | XM | |
---|---|---|---|---|---|---|
SO | 1.873 | 1.026 | 1.267 | 1.974 | 0.815 | |
OR | 0.005 | 1.617 | 1.064 | 1.530 | 2.487 | |
PS | 0.002 | -0.002 | 0.909 | 0.505 | 0.463 | |
KW | 0.026 * | 0.019 | 0.018 | 1.301 | 1.980 | |
TW | -0.003 | 0.003 | 0.001 | 0.029 | 1.029 | |
XM | 0.004 | 0.006 | 0.001 | 0.022 * | 0.010 |
According to the results of the 3D-FCA, the first, second and third principal components can explain 25.91%, 23.08%, and 17.92% of the overall variation, respectively (Figure
The Bayesian cluster analysis showed that the model with K=2 resulted in the highest ΔK value (Figure
Proportion of six P. argenteus populations in each of the two inferred clusters.
Populations | Inferred clusters | Number of individuals | |
---|---|---|---|
1 | 2 | ||
SO | 0.568 | 0.432 | 21 |
OR | 0.474 | 0.526 | 28 |
PS | 0.419 | 0.581 | 12 |
KW | 0.292 | 0.708 | 23 |
TW | 0.494 | 0.506 | 11 |
XM | 0.420 | 0.580 | 24 |
The population demography analysis showed no significant heterozygosity excess observed under all three mutation models by the Wilcoxon sign-rank test (P>0.05), which suggested that P. argenteus should be in mutation-drift equilibrium (Table
Results of Wilcoxon’s heterozygosity excess test, Mode shift indicator for a genetic bottleneck in six P. argenteus populations.
Populations | Wilcoxon sign-rank test | Mode shift | ||
---|---|---|---|---|
IAM | TPM | SMM | ||
SO | 0.004 | 0.469 | 0.531 | L |
OR | 0.004 | 0.531 | 0.711 | L |
PS | 0.008 | 0.234 | 0.469 | L |
KW | 0.148 | 0.961 | 0.996 | L |
TW | 0.020 | 0.289 | 0.289 | L |
XM | 0.004 | 0.004 | 0.945 | L |
The degree of genetic variation is particularly important for the sustainability and evolution of species, and the strong correlation between genetic diversity and overall fitness has been reported (
Microsatellite markers have demonstrated to be highly sensitive for detecting the population structure of fish (
In conclusion, high genetic homogeneity among six P. argenteus populations was detected, and the contemporary genetic structure of the species revealed in this study can preliminarily improve the genetic knowledge and provide a firm basis to guide fishery stock management in the Indo-Pacific Ocean. Unfortunately, only six geographical populations of P. argenteus were collected, which is not sufficient for an even sampling throughout its entire distribution in the Indo-Pacific Ocean. To describe the phylogeographic pattern of P. argenteus, additional representative populations should be collected for further analysis.
The present study could not have been performed without assistance from Dr Pengfei Li, Dr Fozia Khan Siyal, and Professor Weizhong Chen during the collection of P. argenteus specimens. We sincerely thank the reviewers and subject editor, whose comments greatly improved the manuscript. The work was supported by the National Natural Science Foundation of China (41776171), the International Science & Technology Cooperation Program of China (2015DFR30450), the National Programme on Global Change and Air-Sea Interaction (GASI-02-SCS-YSWspr/aut), and the Scientific Research Foundation of Third Institute of Oceanography, SOA (2016010). All authors declare that we have no conflict of interest.