Hindawi International Journal of Zoology Volume 2017, Article ID 5976421, 7 pages https://doi.org/10.1155/2017/5976421 Research Article Population Genetic Structure and Genetic Diversity in Twisted-Jaw Fish, Belodontichthys truncatus Kottelat & Ng, 1999 (Siluriformes: Siluridae), from Mekong Basin Surapon Yodsiri,1,2 Komgrit Wongpakam,1,2 Adisak Ardharn,1,2 Chadaporn Senakun,1,2 and Sutthira Khumkratok1,2 1 Walai Rukhavej Botanical Research Institute, Mahasarakham University, Kantharawichai District, Maha Sarakham 44150, Thailand 2Biodiversity and Conservation Research Unit, Walai Rukhavej Botanical Research Institute, Mahasarakham University, Kantharawichai District, Maha Sarakham 44150, Thailand Correspondence should be addressed to Komgrit Wongpakam; komgrit [email protected] Received 15 February 2017; Accepted 11 July 2017; Published 16 August 2017 Academic Editor: Marco Cucco Copyright © 2017 Surapon Yodsiri et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Mekong River and its tributaries possess the second highest diversityinfishspeciesintheworld.However,thefishbiodiversity in this river is threatened by several human activities, such as hydropower plant construction. Understanding the genetic diversity and genetic structure of the species is important for natural resource management. Belodontichthys truncatus Kottelat & Ng is endemic to the Mekong River basin and is an important food source for people in this area. In this study, the genetic diversity, genetic structure, and demographic history of the twisted-jaw fish, B. truncatus, were investigated using mitochondrial cytochrome b gene sequences. A total of 124 fish specimens were collected from 10 locations in the Mekong and its tributaries. Relatively high genetic diversity was found in populations of B. truncatus compared to other catfish species in the Mekong River. The genetic structure analysis revealed that a population from the Chi River in Thailand was genetically significantly different from other populations, which is possibly due to the effect of genetic drift. Demographic history analysis indicated that B. truncatus has undergone recent demographic expansion dating back to the end of the Pleistocene glaciation. 1. Introduction fish is caught and exported to Thailand [4]. However, there is no information on the genetic diversity and genetic structure The Mekong is the second most biodiverse river for fish of this important fish, despite being important for natural species. It has been estimated that more than 877 fish resource management [5]. species can be recorded in the Mekong and its tributaries [1]. However, many species are under threat due to human- In this study, we used the mitochondrial cytochrome b mediated environmental change, such as hydropower dam (cyt b) sequences to examine the genetic diversity, genetic construction [1, 2]. structure, and demographic history of B. truncatus in the The twisted-jaw catfish (Belodontichthys truncatus Kotte- Mekong and two of its tributaries, the Chi and Mun Rivers lat & Ng) is endemic to the Mekong basin [3]. Two species in northeastern Thailand. Previous studies indicated that of the genus Belodontichthys are found in the Mekong and cyt b sequences can be successfully used to infer genetic its tributaries, including B. dinema Bleeker, 1851, and B. structure and demographic history of freshwater fishes [6– truncatus. The former species occur in central and southern 8]. The information presented in this study will be useful for Thailand,Malaysia,Sumatra,andBorneo,whilethelatter the management of B. truncatus. In addition, because this species is found in northeast Thailand, Lao PDR, Cambodia, species is widely distributed in the Mekong and its tributaries, and Vietnam [3]. Belodontichthys truncatus is a very impor- understanding its genetic structure and demographic history tant species for fisheries in Lao PDR and Cambodia where the would shed some light on the effect of historical change 2 International Journal of Zoology ∘ ∘ ∘ ∘ ∘ ∘ 101 0 0 E 102 0 0 E 103 0 0 E 104 0 0 E 105 0 0 E 106 0 0 E ∘ ∘ 19 0 0 N 19 0 0 N N ∘ ∘ 18 0 0 N 18 0 0 N ∘ ∘ 17 0 0 N 17 0 0 N ∘ ∘ 16 0 0 N 16 0 0 N ∘ ∘ 15 0 0 N 15 0 0 N ∘ ∘ 14 0 0 N 14 0 0 N ∘ ∘ 13 0 0 N 13 0 0 N ∘ ∘ 12 0 0 N 12 0 0 N ∘ ∘ 11 0 0 N 11 0 0 N (km) 025 50 100 150 200 ∘ ∘ 10 0 0 N 10 0 0 N ∘ ∘ ∘ ∘ ∘ ∘ 101 0 0 E 102 0 0 E 103 0 0 E 104 0 0 E 105 0 0 E 106 0 0 E Dam Tributary Location Country boundary Mekong River Figure 1: Sampling locations for twisted-jaw fish, Belodontichthys truncatus, are used in this study. Details of sampling sites are provided in Table 1. (e.g., Pleistocene climatic and environmental change) on fish Lake in Cambodia. Specimens were identified following the biodiversity. description of Belodontichthys truncatus by Kottelat & Ng [3]. 2. Materials and Methods 2.2. DNA Extraction, Polymerase Chain Reaction, and 2.1. Specimen Collection and Identification. Atotalof124fish Sequencing. Genomic DNA was extracted from the tissue specimens were collected from seven locations in Thailand using the Genomic DNA Extraction mini kit (RBC Bio- Science, Xindian City, Taiwan). A fragment of the cytochrome and Cambodia (Table 1 and Figure 1). Among these locations, b(cytb)gene was amplified using the primers Glu31 (5 GTG- onewasfromtheChiRiverandonefromtheMunRiver;both of these are in northeastern Thailand. Three sites were from ACTTGAAAAACCACCGTT3 )andCat.Thr29(5ACC- the Mekong River along the Thailand-Lao PDR border, one TTCGATCTCCTGATTACAAGAC3 ) [9]. The amplifi- from the Mekong River in Cambodia and one from Tonle Sap cation reaction with a total volume of 50 lcontained International Journal of Zoology Table 1: Details of sampling locations for Belodontichthys truncatus used in this study and haplotype and nucleotide diversity. Geographic Collection Haplotype Location (code) River Nucleotide diversity region date diversity ∘ 15 47 24.82 N Yasothon Province, Thailand (CHYT) Chi ∘ 2 10/11/2014 0 0 104 08 34.04 E ∘ Mueang District, Maha Sarakham Province 16 13 18.29 N Chi ∘ 214/08/20140 0 (CHMK) 103 20 3.13 E ∘ 15 40 38.17 N At Samat District, Roi Et Province (CHRO1) Chi ∘ 4 6/11/2014 0.8333 ± 0.2224 0.001958 ± 0.001641 104 06 48.87 E ∘ 15 41 41.50 N Phanom Phrai District, Roi Et Province (CHRO2) Chi ∘ 14 10/11/2014 0.5055 ± 0.1581 0.003413 ± 0.002077 103 07 38.64 E ∘ 15 14 29.71 N Ubon Ratchathani Province, Thailand (MUUB) Mun ∘ 10 11/11/2014 0.8667 ± 0.0850 0.00205 ± 0.00141 104 57 20.64 E ∘ 18 01 28.29 N Nong Khai Province Thailand (MKNK) Mekong ∘ 13 8/11/2014 0.9487 ± 0.0506 0.00405 ± 0.00242 101 52 54.34 E ∘ Khong Chiam District, Ubon Ratchathani 15 23 26.82 N Mekong ∘ 13 17/10/2014 0.9359 ± 0.0507 0.00401 ± 0.00240 Province, Thailand (MKUB) 105 29 39.14 E ∘ Khemarat District, Ubon Ratchathani Province, 16 02 32.16 N Mekong ∘ 28 14/10/2014 0.8810 ± 0.0367 0.00271 ± 0.00165 Thailand (MKKR) 105 13 32.39 E ∘ 11 33 28.18 N Phnom Penh Province, Cambodia (MKCDPP) Mekong ∘ 12 18/11/2014 0.8788 ± 0.0751 0.00242 ± 0.00158 104 56 14.13 E ∘ Tonle Sap Lake, Pursat Province, Cambodia Tonle Sap 12 02 19.24 N ∘ 26 15/11/2014 0.8062 ± 0.0594 0.00365 ± 0.00212 (MKCDPO) Lake 104 43 43.54 E Total 124 0.9765 ± 0.0051 0.003179 ± 0.001826 3 4 International Journal of Zoology 2 l MgCl2 (50 mM), 5 lof10xPCRbuffer,1.6lofmixed dNTPs (10 M), 2 lofeachprimer(10M), 0.4 lofTaq DNA polymerase (5 u/l), and 2 lDNAtemple.Thetem- ∘ perature profile was as follows: 94 Cfor3min,followedby ∘ ∘ ∘ 35 cycles of 94 C for 30 seconds, 48 Cfor1min,and72C ∘ for 1.30 min with a final extension at 72 C for 7 min [10]. The PCR products were checked by 1% agarose gel electrophoresis and purified using a High Yield Gel/PCR DNA fragment extraction kit (RBC BioScience, Taiwan). Sequencing was performed at the Macrogen DNA sequencing service (Seoul, Mekong River Korea) using the same primers as in the PCR. Chi River Mun River 2.3. Data Analysis. Afragmentof1,024bpofthecyt Figure 2: Median joining (MJ) network of 124 mitochondrial b gene was obtained from 124 specimens. Sequences cytochrome b (cyt b) sequences of Belodontichthys truncatus.Each were deposited in GenBank under the accession numbers haplotype is represented by a circle and sizes of circles are relative to KY607016–KY607139. Genealogical relationships between number of individuals sharing a specific haplotype. Haplotypes are haplotypes were estimated using a median joining (MJ) labelled according to the river. network (Bandelt et al., 1999) calculated using Network v 4.6.1.0 (http://www.fluxus-engineering.com). Haplotype 2500 diversity and nucleotide diversity were calculated using 2000 Arlequin ver. 3.5 [11]. The population pairwise ST calculated = 0.838 Tau ∗∗ in Arlequin was used to infer the genetic structure. The Fu’s F = −26.2649 1500 S ∗∗ significance test statistic was obtained from 1,023 permu- Tajima’s D = −2.5364 ∗∗ tations. To avoid bias, due to a small sample size, popu- 1000 P < 0.001 lations with less than five specimens were omitted from the genetic structure analysis. A Mantel test [12] was used 500 to determine the relationship between the genetic distance 0 (ST from Arlequin) and the geographical distance (km) for 0 5 10 15 20 25 30 an isolation-by-distance (IBD) model. The Mantel test was implemented in IBD ver. 1.52 [13] using 1,000 randomizations.