Complete Mitochondrial DNA Genome of Nine Species of Sharks and Rays and Their Phylogenetic Placement among Modern Elasmobranchs.

Vasiliki Kousteni,Sofia Mazzoleni,Michail Rovatsos,Katerina Vasileiadou

doi:10.3390/genes12030324

Vasiliki Kousteni, Sofia Mazzoleni + Show 2 more

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https://doi.org/10.3390/genes12030324

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Journal: Genes	Publication Date: Feb 24, 2021
Citations: 32	License type: CC BY 4.0

Affiliation: Charles University, Hellenic Centre for Marine Research

Abstract

Chondrichthyes occupy a key position in the phylogeny of vertebrates. The complete sequence of the mitochondrial genome (mitogenome) of four species of sharks and five species of rays was obtained by whole genome sequencing (DNA-seq) in the Illumina HiSeq2500 platform. The arrangement and features of the genes in the assembled mitogenomes were identical to those found in vertebrates. Both Maximum Likelihood (ML) and Bayesian Inference (BI) analyses were used to reconstruct the phylogenetic relationships among 172 species (including 163 mitogenomes retrieved from GenBank) based on the concatenated dataset of 13 individual protein coding genes. Both ML and BI analyses did not support the “Hypnosqualea” hypothesis and confirmed the monophyly of sharks and rays. The broad notion in shark phylogeny, namely the division of sharks into Galeomorphii and Squalomorphii and the monophyly of the eight shark orders, was also supported. The phylogenetic placement of all nine species sequenced in this study produced high statistical support values. The present study expands our knowledge on the systematics, genetic differentiation, and conservation genetics of the species studied, and contributes to our understanding of the evolutionary history of Chondrichthyes.

Highlights

Cartilaginous fish (Class Chondrichthyes) consist a group of vertebrates that demonstrate an old radiation, dating back about 400 million years [1,2]
Both Maximum Likelihood (ML) and Bayesian Inference (BI) analyses were used to reconstruct the phylogenetic relationships among 172 species based on the concatenated dataset of 13 individual protein coding genes
Due to the fact that almost 1/3 of the assessed species face extinction risk [2,23] and further 63 Data Deficient (DD) species were predicted to be threatened based on correlates of International Union for the Conservation of Nature (IUCN) threat status, chondrichthyans comprise the most-imperiled class among all vertebrates [23]

Summary

Introduction

Cartilaginous fish (Class Chondrichthyes) consist a group of vertebrates that demonstrate an old radiation, dating back about 400 million years [1,2]. Due to the fact that almost 1/3 of the assessed species face extinction risk [2,23] and further 63 Data Deficient (DD) species were predicted to be threatened based on correlates of IUCN threat status, chondrichthyans comprise the most-imperiled class among all vertebrates [23]. This highlights the importance of preserving their biodiversity and shedding light on their phylogenetic relationships [23] by prioritizing especially threatened species as they embody significant amounts of unique evolutionary history [2]

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