Genetic diversity of purple-legged shovel-nosed lobster Thenus unimaculatus in Thailand

Abstract

Thenus unimaculatus or a purplelegged shovel-nosed lobster is one of the three Thenus species found in Thailand. Shovelnosed lobsters have been increasingly consumed and this could give a great threat to T. Unimaculatus. This species has a narrow range of distribution, found only in the Andaman Sea. Genetic diversity study of the purple-legged shovel-nosed lobster is therefore needed for evaluating its current genetic status. In this study, 71 specimens of T. unimaculatus were collected from five provinces along the Andaman Sea coastline. 12S ribosomal RNA (12S rRNA) and cytochrome C oxidase subunit I (COI) mitochondrial genes were PCR amplified. The 12S rDNA and the COI nucleotide sequence alignments of 60 and 70 samples, respectively, were successfully prepared, suggesting that the parsimony informative sites of COI gene was higher than that of 12S rDNA. Phylogenetic analysis using Maximum Likelihood method revealed that populations of T. unimaculatus in Thailand are fairly homogenised. This blended genetic diversity among the five provincial populations indicates that there is a circulation of the planktonic larvae, resulting from two different patterns of sea currents of the Andaman Sea.