Characterization of the mitochondrial genome of Megalobrama terminalis in the Heilong River and a clearer phylogeny of the genus Megalobrama

Xuesong Hu,Zining Meng,Jingou Tong,Chitao Li,Peixian Luan,Zhiying Jia,Shihui Wang,Chunhua Cao,Yanlong Ge,Lianyu Shi,Mei Shang

doi:10.1038/s41598-019-44721-2

Abstract

Megalobrama terminalis distributed in Sino-Russian Heilong-Amur River basin has decreased dramatically in the last few decades. It has been listed in the Red Book of the Russian Federation as an endangered fish species. Here, the complete mitochondrial (mt) genome sequence of M. terminalis in the Heilong River (MTH) was first determined and characterized. Additionally, we identified a population-specific single nucleotide polymorphism (SNP) locus in MTH which could effectively separate MTH from the six other populations of the genus Megalobrama in the absence of hybridization. Moreover, phylogenetic analyses determined that the Xi River M. hoffmanni is located at the basal branch of the clade, and the rest of the group is divided into two assemblages, namely, one containing M. terminalis from Qiantang River and Jinsha River Reservoir/Longxi River M. Pellegrini/MTH and the other containing M. amblycephala from Liangzi Lake and Yi River. We clarify the intraspecies identity of MTH and construct a clearer phylogeny of the genus Megalobrama, which will contribute to the germplasm identification, protection and development of MTH in the future.

Highlights

Pollution have caused the habitats of Faluo to decrease dramatically[7]
In a phylogenetic study of Eastern Asian Cyprinidae based on mitochondrial CYTB, M. terminalis and M. amblycephala are sister taxa that form a clade with M. pellegrini[8]
In another study based on mitochondrial CYTB, Xie et al proposed that M. terminalis was closely related to M. pellegrini but not to M. amblycephala[9]

Summary

Introduction

Pollution have caused the habitats of Faluo to decrease dramatically[7]. Currently, only dozens of individuals of Faluo can be captured per year near Fuyuan city (134°28′E, 48°37′N) (Fig. 1), which is located in Heilongjiang Province. Evidence reflecting the molecular variations in Faluo and the phylogenetic relationships between Faluo and other fish species within the genus Megalobrama is scarce. On the other hand, regarding the interspecific relationships within the genus Megalobrama, most of the available data suggest close relationships among M. terminalis, M. pellegrini and M. amblycephala, and M. hoffmanni is more distantly related to the other species[8,9,10,11,12,13,14]. In a phylogenetic study of Eastern Asian Cyprinidae based on mitochondrial CYTB, M. terminalis and M. amblycephala are sister taxa that form a clade with M. pellegrini[8]. In another study based on mitochondrial CYTB, Xie et al proposed that M. terminalis was closely related to M. pellegrini but not to M. amblycephala[9]. The single nucleotide variations, specific markers and phylogeny between MTH and six other representative geographic samples within the genus Megalobrama were analyzed from a mt genome perspective

Methods

Results

Conclusion