Abstract
The complete mitochondrial genome of the Queensland seahorse Hippocampus queenslandicus Horne, 2001 (Gasterosteiformes: Syngnathidae) has been amplified and sequenced in this study. The mitogenome was 16,527 bp long with protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes and a non-coding control region. The overall base composition of the genomes was 32.2% for A, 30.1% for T, 14.9% for G, and 22.8% for C with an A + T-rich characteristic (62.3%). According to the phylogenetic analysis, H. queenslandicus showed a closer genetic relationship with H. spinosissimus.
The Queensland seahorse, Hippocampus queenslandicus Horne (Citation2001) (Gasterosteiformes: Syngnathidae), is primary distributed in the north Queensland waters of the Great Barrier Reef, Australia (Horne Citation2001). Hippocampus queenslandicus is a deeper-water seahorse with a depth of 30–50m, usually located on a sponge or seagrass habitat, and attached to hard and soft coral species (Horne Citation2001). International trade of this species is monitored through a licensing system and a minimum size of 10 cm applies (Froese & Pauly Citation2016). However, the genetic information of H. queenslandicus has rarely been reported at present. In this study, the complete mitochondrial genome of H. queenslandicus was amplified and sequenced, which had been deposited in GenBank with accession no.KX685110.
The specimen was purchased from Chengdu Lotus Pond Herbal Medicine Market (Chengdu, Sichuan provice), and identified as H. queenslandicus based on its morphometric features and DNA barcoding technology. The sample used in this study was with Animal Ethics approval for experimentation granted by Chengdu University of Traditional Chinese Medicine. The complete mitogenome of H. queenslandicus was 16,527 bp in length, and contained 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and a non-coding control region (D-loop), with identical gene arrangement and similar length as observed in other seahorse species (Chang et al. Citation2013; Song & Mabuchi Citation2014; Wang et al. Citation2014, Citation2015; Cheng et al. Citation2015; Zhang et al. Citation2015a, Citation2015b). Most of the genes were encoded on the heavy DNA strand (H-strand), excluding eight tRNA genes and ND6 gene. The overall base composition of the mitogenome was 32.2% for A, 30.1% for T, 14.9% for G, and 22.8% for C with an A + T-rich characteristic (62.3%) as that of other vertebrate mitochondrial genomes. All protein-coding genes, except for COI that was started with GTG, were initiated by ATG. Seven of 13 protein-coding genes were terminated with an incomplete stop codon T/TA, and six genes terminated with a complete TAA/TAG. The mitogenome of H. queenslandicus contained a 12S rRNA (937 bp) and a 16S rRNA (1698 bp), locating between tRNA-Phe and tRNA-Leu separated by tRNA-Val. The non-coding control region, which was 878 bp in length, was located between tRNAPro and tRNAPhe genes. Among protein-coding genes, ND5 was the longest (1836bp), and ATP8 was the shortest (168 bp).
The phylogenetic analysis of 13 Syngnathidae species was performed using NJ algorithm based on the whole mitogenomes (). The phylogenetic tree showed that H. queenslandicus had a closer genetic relationship with H. spinosissimus than other seahorse species.
Figure 1. Phylogenetic tree of 13 Syngnathidae species constructed with the whole mitogenome using MEGA 7 (Temple University, Philadelphia, USA). Syngnathus schlegeli was used to the root the trees. Bootstrap values generated from 1000 replicates for NJ analysis.
Acknowledgements
This work was supported by National Natural Science Foundation of China under Grant No. 81541167 and Science and Technology Development Fund of Chengdu University of Traditional Chinese medicine under Grant No. 030029140.
Disclosure statement
The authors declare no any conflict of interest in the preparation and execution of this manuscript.
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References
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