The Complete Mitochondrial Genome Sequences of the Philomycus bilineatus (Stylommatophora: Philomycidae) and Phylogenetic Analysis.

Tiezhu Yang,Hellen Lucas Mzuka,Heding Shen,Bingning Gu,Guolyu Xu,Yanmei Shi

doi:10.3390/genes10030198

Abstract

The mitochondrial genome (mitogenome) can provide information for phylogenetic analyses and evolutionary biology. We first sequenced, annotated, and characterized the mitogenome of Philomycus bilineatus in this study. The complete mitogenome was 14,347 bp in length, containing 13 protein-coding genes (PCGs), 23 transfer RNA genes, two ribosomal RNA genes, and two non-coding regions (A + T-rich region). There were 15 overlap locations and 18 intergenic spacer regions found throughout the mitogenome of P. bilineatus. The A + T content in the mitogenome was 72.11%. All PCGs used a standard ATN as a start codon, with the exception of cytochrome c oxidase 1 (cox1) and ATP synthase F0 subunit 8 (atp8) with TTG and GTG. Additionally, TAA or TAG was identified as the typical stop codon. All transfer RNA (tRNA) genes had a typical clover-leaf structure, except for trnS1 (AGC), trnS2 (TCA), and trnK (TTT). A phylogenetic analysis with another 37 species of gastropods was performed using Bayesian inference, based on the amino acid sequences of 13 mitochondrial PCGs. The results indicated that P. bilineatus shares a close ancestry with Meghimatium bilineatum. It seems more appropriate to reclassify it as Arionoidea rather than Limacoidea, as previously thought. Our research may provide a new meaningful insight into the evolution of P. bilineatus.

Highlights

The mitochondrial genome is a closed circular structure with molecules ranging from approximately from 14,000 to 18,000 bp in length
As in other Cenogastropoda, the mitogenomes are comprised of 38 genes: 13 protein-coding genes (PCGs), 23 transfer RNA (tRNA), two rRNAs (12S and 16S), and two non-coding regions (Table 1)
The mitogenome is composed of the typical structure of 13 PCGs, two rRNAs, is 14,347 bp in length

Summary

Introduction

The mitochondrial (mt) genome is a closed circular structure with molecules ranging from approximately from 14,000 to 18,000 bp in length. Since mtDNA is expressed as matrilineal inheritance, the structure and proportion of mitochondrial DNA can better reflect the genetic characteristics of populations [1], it does not reflect the genetic information of the male population [2,3]. It generally contains two ribosomal RNA genes (12S rRNA and 16S rRNA), 22 transfer RNA genes (tRNAs), 13 protein-coding genes (PCGs), and one typical non-coding control region with regulatory elements necessary for transcription and replication [4]. The mtDNA control region contains the origin of replication of one strand, and the origin of transcription

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