Integrative Zoology 2019; 14: 318–322 doi: 10.1111/1749-4877.12331 1 LETTER TO THE EDITOR 1 2 2 3 3 4 4 5 5 6 6 7 Isolation and characterization of polymorphic microsatellite 7 8 8 9 loci from pale-edged stingray, Telatrygon zugei (Elasmobranchii, 9 10 10 11 Dasyatidae) 11 12 12 13 13 14 Fanglei SHI1,2*, Hui WANG3*, Atsuko YAMAGUCHI4, Baowei ZHANG3 and Jie ZHANG1 14 15 15 1 16 Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China, 16 2 3 4 17 University of Chinese Academy of Sciences, Beijing, China, School of Life Science, Anhui University, Hefei, China and Faculty 17 18 of Fisheries, Nagasaki University, Nagasaki, Japan 18 19 19 20 20 21 21 22 INTRODUCTION 2007). Despite the combination of known high biodi- 22 23 versity and heavy exploitation of elasmobranchs in Chi- 23 24 Sharks, skates and rays originated 400 Ma, with a na, there is little reliable information on the population 24 25 further radiation throughout every ocean, and play a vi- genetics of many shark and ray species. Consequent- 25 26 tal role in maintaining the balance of marine ecosys- ly, clarification of the population structure is crucial for 26 27 tems as top predators (Weigmann 2016). There are more conservation and management, especially for endan- 27 28 than 1000 species of sharks, skates, rays and chimae- gered elasmobranchs. 28 ras in the world, 244 of which are distributed in Chinese 29 Dasyatidae is one of the largest families of elasmo- 29 seas. That is, Chinese chondrichthyan fauna make up 30 branchs, comprising 19 genera and at least 86 living 30 at least one-fifth of the world’s extant species. Recent 31 species. They are distributed circumglobally in tropical, 31 habitat degradation and overexploitation have caused 32 subtropical and temperate waters (Nelson 2006; Last 32 sharp declines in many populations of elasmobranchs 33 et al. 2016). The pale-edged stingray, Telatrygon zugei 33 (White 2007; Dulvy et al. 2017). Environmental chang- 34 (Müller & Henle, 1841), is an inner continental stingray 34 es and loss of oceanic apex predators due to overfishing 35 of the Indo-West Pacific, typically found along the con- 35 could affect the migration routes and distribution of ba- 36 tinental shelf of the Gulf of Thailand, the Java Sea, and 36 toids (rays), resulting in community restructuring in the 37 the coastal waters off southern China and western Japan 37 coastal ecosystem (Yamaguchi et al. 2005; Myers et al. 38 at <100m (Kyne et al. 2012). T. zugei is consumed lo- 38 39 cally but also forms a significant component of the elas- 39 40 mobranch bycatch within the demersal fishery through- 40 41 out its range (White 2007). The fecundity of T. zugei is 41 42 very low, with females usually possessing only a sin- 42 43 Correspondence: Baowei Zhang, School of Life Science, gle embryo (White 2003). Because of high levels of ex- 43 44 Anhui University, Hefei 230039, China. ploitation and low resource resilience, T. zugei is listed 44 45 45 Email: [email protected] as near threatened (NT) by the IUCN (2017). 46 46 Jie Zhang, Key Laboratory of Animal Ecology and Microsatellite markers are widely used co-domi- 47 47 nant genetic markers and have proven to be optimal in 48 Conservation Biology, Institute of Zoology, Chinese Academy 48 assessing population structure for conservation genet- 49 of Sciences, Beijing 100101, China. 49 ics (Harper et al. 2003; Guyomard et al. 2006). In this 50 Email: [email protected] 50 study, we developed 9 highly polymorphic microsatel- 51 *These authors contributed equally to this work. 51 318 © 2018 International Society of Zoological Sciences, Institute of Zoology/ Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd Pale-edged stingray microsatellite loci 1 lite primers in the pale-edged stingray, which will allow along the Indo-West Pacific coastline from 6 locations: 1 2 for investigating the genetic diversity and population Ariake Bay in Japan (JP), the Gulf of Thailand (TLD) 2 3 genetic structure of T. zugei, as well as proposing scien- and the Andaman Sea (ADM), and 3 localities along the 3 4 tific evidence for management and conservation. coast of the East China and South China Seas, includ- 4 5 ing Shandong (SD), Guangdong (GD) and Hainan (HN) 5 6 MATERIALS AND METHODS (Table 1). Primers were tested on 92 T. zugei individu- 6 7 als to check the polymorphism of loci. PCR reactions 7 8 The screening process for microsatellites mainly ad- were performed in 20-μL volumes: 100 to 200 ng of ge- 8 9 hered to the FIASCO protocol (Zane et al. 2002). Ge- nomic DNA, 10 µL 2 × EasyTaq PCR Supermix (Trans- 9 10 nomic DNA was extracted from the fin tissue of one in- Gen Biotech) and 2.5 pmol of each primer pair (forward 10 11 dividual using the DNeasy Blood & Tissue kit (Qiagen). primer fluorescently labeled with FAM, HEX or TAM- 11 12 Approximately 250 ng DNA was digested by MesІ, and RA). The amplification was performed on an Applied 12 13 DNA fragments were ligated to the double-strand MesІ Biosystems (ABI) 2720 thermal cycler under the fol- 13 14 AFLP adaptor (MseI R:5′-GAC GAT GAG TCC TGA lowing conditions: an initial denaturing step at 95 °C for 14 15 G-3′ and MseI F: 5′-TAC TCA GGA CTC AT-3′). Then, 5 min, followed by 30 cycles of 30 s at 95 °C, with the 15 16 these DNA fragments were amplified with AFLP adap- annealing temperature at 50 °C or 55 °C for 30 s, and 40 16 17 tor-specific primers (MseI-N: 5′-GAT GAG TCC TGA s at 72 °C, and a 10-min extension at 72 °C. The PCR 17 18 GTA A-3′) for enrichment. The enriched DNA fragments products were separated on an ABI PRISM 3730 genetic 18 19 were hybridized with 5′-biotinylated probe (AC)12 and analyzer (Applied Biosystems) with a GS500 size stan- 19 20 (AG)12 for selection. The hybrid was restored to a dou- dard. 20 21 ble-strand pattern by PCR. The DNA strand was ligated To test the transferability of the microsatellite loci, 21 22 into the pEASY-T1 Simple Cloning Vector (TransGen) we also tested these loci for cross-amplification us- 22 23 and transformed into Trans5α chemically competent ing species from a different genus: Hemitrygon akajei, 23 24 cells (TransGen). The cells were plated on LB-ampicil- Hemitrygon bennetti, Neotrygon kuhlii and Himantura 24 25 lin plates supplemented with IPTG and X-Gal. Recom- microphthalma. Extractions and genotyping were con- 25 26 binants were screened by PCR with vector primers and ducted following the same protocol as above. 26 27 AC/AG primers. Clones with PCR products showing 27 Genotypes were analyzed using GENMARKER (ver- 28 multiple bands in 2% agarose electrophoresis were con- 28 sion 1.3, SoftGenetics LLC). Micro-Checker (van Oos- 29 sidered as positive clones and picked out for sequenc- 29 terhout et al. 2004) was used to detect genotyping errors 30 ing. Sequences were checked for microsatellites by 30 due to null alleles, stuttering or allele dropout. The num- 31 Tandem Repeat Finder (Benson 1999). We eliminated 31 ber of alleles (N ), observed heterozygosity (H ), ex- 32 sequences with any of the following conditions: (i) re- A O 32 pected heterozygosity (H ) and polymorphic information 33 peat units number less than 10; (ii) either side of flank- E 33 content (PIC) were calculated with software Cervus 3.03 34 ing sequence was not long enough for designing primer; 34 (Marshall et al. 1998). Departure from Hardy–Weinberg 35 and (iii) the core sequence had compound repeat units, 35 equilibrium (HWE) and linkage disequilibrium (LD) 36 such as diuncleotide and triuncleotide compound repeat 36 were tested with GENEPOP v3.4 (Raymond & Rousset 37 motifs. 37 1995). 38 A total of 92 T. zugei individuals were collected 38 39 39 40 40 41 41 42 Table 1 Sampling site information 42 43 43 Abbreviation Locality (sea area) Longitude Latitude Sample size 44 44 45 JP Japan (Arike Sound) 130.14–130.60°E 32.62–33.18°N 20 45 46 SD Shandong, China (Yellow Sea) 118.92–122.55°E 36.95–37.86°N 6 46 47 GD Fujian and Guangdong, China (East China Sea) 113.62–1189.20°E 22.45–25.37°N 14 47 48 HN Hainan, China (South China Sea) 108.63–110.15°E 20.05–18.25°N 20 48 49 49 TLD Thailand (Gulf of Thailand) 100.60–101.56°E 12.59–13.51°N 12 50 50 51 ADM Andaman Sea (Indian Ocean) 100.60–101.56°E 12.59–13.51°N 20 51 © 2018 International Society of Zoological Sciences, Institute of Zoology/ 319 Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd F. Shi et al. 1 RESULTS loci. We also detected the genetic diversity of the 9 loci 1 2 in 6 populations. The number of alleles (NA) per locus 2 3 A total of 108 positive clones were picked up for se- ranged from 6 (locus DzuI45) to 56 (locus DzuI25). Ob- 3 quencing and 90 of them were sequenced successful- 4 served heterozygosities (HO) and expected heterozy- 4 ly; 50 unique sequences were chosen for primer de- 5 gosities (HE) ranged from 0.429 (locus DzuI57) to 1.0 5 6 sign and 20 primers were designed using Premier 5.