The complete mitochondrial genome of endangered Assam Roofed Turtle, Pangshura sylhetensis (Testudines: Geoemydidae): Genomic features and Phylogeny

Abstract

Assam Roofed Turtle, Pangshura sylhetensis is an endangered and least studied species endemic to India and Bangladesh. The genomic feature of P. sylhetensis mitogenome is still anonymous to the scientific community. The present study decodes the first complete mitochondrial genome of P. sylhetensis (16,568 bp) by using next-generation sequencing. This de novo assembly encodes 13 Protein-coding genes (PCGs), 22 transfer RNAs (tRNAs), two ribosomal RNAs (rRNAs), and one control region (CR). Most of the genes were encoded on the majority strand, except NADH dehydrogenase subunit 6 (nad6) and eight tRNAs. Most of the PCGs were started with an ATG initiation codon, except for Cytochrome oxidase subunit 1 (cox1) and NADH dehydrogenase subunit 5 (nad5) with GTG. The study also found the typical cloverleaf secondary structure in most of the tRNA genes, except for serine (trnS1) with lack of conventional DHU arm and loop. Both, Bayesian and Maximum-likelihood topologies showed distinct clustering of all the Testudines species with their respective taxonomic ranks and congruent with the previous phylogenetic hypotheses (Pangshura and Batagur sister taxa). Nevertheless, the mitogenomic phylogeny with other amniotes corroborated the sister relationship of Testudines with Archosaurians (Birds and Crocodilians). Additionally, the mitochondrial Gene Order (GO) analysis indicated that, most of the Testudines species showed plesiomorphy with typical vertebrate GO.