Genetic structure of the endangered Irrawaddy dolphin (Orcaella brevirostris) in the Gulf of Thailand

Ornate threadfin bream (Nemipterus hexodon) is an economically important fishery species in Southeast Asia. In Thailand, N. hexodon decreased dramatically due to overexploitation for commercial purposes. To construct an effective sustainable management plan, genetic information is necessary. Thus, in our study, the population genetic structure and demographic history of N. hexodon were investigated using 419 bp of the mitochondrial DNA sequence in cytochrome oxidase subunit I gene (mtDNA COI). A total of 142 samples was collected from nine localities in the Gulf of Thailand (Chonburi, Samut Songkhram, Surat Thani, Nakhon Si Thammarat, Songkhla), and the Andaman Sea (Satun, Trang, Krabi, Phang Nga). Fourteen polymorphic sites defined 18 haplotypes, revealing a high haplotype diversity and low nucleotide diversity among nine localities. The Analysis of molecular variance (AMOVA) analysis, pairwise FST, and minimum spanning network result revealed that the genetic structure of N. hexodon was separated into two populations: the Gulf of Thailand and the Andaman Sea population. The genetic structure of N. hexodon can be explained by a disruption of gene flow from the geographic barrier and the Pleistocene isolation of the marine basin hypothesis. Neutrality tests, Bayesian skyline analysis, mismatch distribution, and the estimated values of population growth suggested that N. hexodon had experienced a population expansion. The genetic information would certainly help us gain insight into the population genetic structure of N. hexodon living on the coast of Thailand.

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Mitochondrial DNA diversity and population structure in the Irrawaddy dolphin (Orcaella brevirostris ) from the Gulf of Thailand and the Mekong River

Marine Mammal Science ◽

10.1111/mms.12518 ◽

2018 ◽

Vol 35 (1) ◽

pp. 300-310 ◽

Cited By ~ 1

Author(s):

Susana Caballero ◽

Verné Dove ◽

Justine Jackson-Ricketts ◽

Chalatip Junchompoo ◽

Sarah Cohen ◽

...

Keyword(s):

Mitochondrial Dna ◽

Population Structure ◽

Mekong River ◽

Gulf Of Thailand ◽

Dna Diversity ◽

Irrawaddy Dolphin ◽

The Gulf Of Thailand

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Population genetic structure of blue swimming crab (Portunus pelagicus) in the Gulf of Thailand

Biodiversitas Journal of Biological Diversity ◽

10.13057/biodiv/d210943 ◽

2020 ◽

Vol 21 (9) ◽

Author(s):

VERAKIAT SUPMEE ◽

AMONSAK SAWUSDEE ◽

PRADIT SANGTHONG ◽

JUTHAMAS SUPPAPAN

Keyword(s):

Genetic Structure ◽

Population Genetic Structure ◽

Population Genetic ◽

Nuclear Dna ◽

Demographic History ◽

Gulf Of Thailand ◽

Swimming Crab ◽

Portunus Pelagicus ◽

Significant Difference ◽

The Gulf Of Thailand

Abstract. Supmee V, Sawusdee A, Sangthong P, Suppapan J. 2020. Population genetic structure of Blue Swimming Crab (Portunus pelagicus) in the Gulf of Thailand. Biodiversitas 21: 4260-4268. The Blue Swimming Crab (Portunus pelagicus) is an important commercial fishery product in the Gulf of Thailand. To provide a strategy for management, information on genetic features is needed. In our study, the population genetic structure and demographic history of the P. pelagicus living in the Gulf of Thailand were analyzed based on the variation of the nucleotide sequence of the mitochondrial DNA in the control region (mtDNA CR). Ninety-seven samples were collected from 5 sampling sites: Rayong, Chonburi, Chumphon, Surat Thani, and Nakhon Si Thammarat provinces in the Gulf of Thailand. Forty-nine haplotypes were identified and 39 private haplotypes were found. An AMOVA showed no genetic structure among populations. The pairwise FST also indicated no statistically significant difference between all possible regional combinations. The topology of a minimum spanning network revealed a star-like topology that was not separated by geographic structure. The historical demographic analysis revealed a stable population size for a long period and followed by a very recent expansion. An absence of a population structure of the P. pelagicus was possibly caused by a high level of gene flow. The results of this study differ from previous studies that used genetic markers in nuclear DNA. Thus, to clear the genetic structure information of P. pelagicus in the Gulf of Thailand, we suggested that more sensitive markers to detect genetic structure should be used in further analysis.

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