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Dryad

Data from: The first complete mitochondrial genome of the Indian Tent Turtle, Pangshura tentoria (Testudines: Geoemydidae): characterization and comparative analysis

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Nov 15, 2019 version files 405.48 KB

Abstract

Characterization of complete mitogenome is a widely used genomics study for species delineation and evolutionary research. However, the sequences and structural motifs contained within the mitogenome have been rarely examined to understand the phylogeny and evolutionary history among Testudines. Hence, the mitogenomic features of several Testudines taxa are still anonymous to the scientific communities. The present study decodes the first complete mitochondrial genome of the Indian Tent Turtle, Pangshura tentoria (16,657 bp) by using next-generation sequencing. This denovo assembly encodes 37 genes: 13 protein coding genes (PCGs), 22 transfer RNA (tRNAs), two ribosomal RNA (rRNAs), and one control region (CR). The mitogenome contained 19 intergenic spacer and six overlapping regions. Most of the genes were encoded on majority strand, except for one PCG (NADH dehydrogenase subunit 6) and eight tRNAs. Most of the PCGs were started with an ATG initiation codon, except for cytochrome oxidase subunit 1 with ‘GTG’ and NADH dehydrogenase subunit 5 with ‘ATA’. The termination codons, ‘TAA’ and ‘AGA’ were observed in NADH dehydrogenase subunit 4l and NADH dehydrogenase subunit 6 respectively. The Relative Synonymous Codon Usage analysis revealed the maximum abundance of Alanine, Isoleucine, Leucine, and Threonine. The non-synonymous/synonymous ratios were <1 in all PCGs, which indicates strong negative selection among all Geoemydid species. The study also found the typical cloverleaf secondary structure in most of the tRNA genes, except for Serine (trnS1) with lack of the conventional DHU arm. The Wobble base pairing was observed in the different stems (DHU, acceptor, and anticodon) of 11 tRNAs. The comparative study of Geoemydid mitogenomes revealed the occurrence of tandem repeats was frequent in the 3´ end of CR. Further, two copies of a unique tandem repeat ‘TTCTCTTT’ were identified in P. tentoria. The Bayesian and Maximum Likelihood phylogenetic trees using concatenation of 13 PCGs revealed the close relationships of P. tentoria with Batagur trivittata in the studied dataset. All the Geoemydid species showed distinct clustering with high bootstrap support congruent with previous evolutionary hypotheses. We suggest that the generations of more mitogenomes of Geoemydid species, especially for Batagurinae subfamily, are required to improve our understanding their in-depth phylogenetic and evolutionary relationships.