Mitochondrial genome of the critically endangered Baer\u2019s Pochard, Aythya baeri, and its phylogenetic relationship with other Anatidae species

Dawei Liu,Yiling Fei,Chunping Xie,Senlin Hou,Yongwu Zhou

doi:10.1038/s41598-021-03868-7

Abstract

Historically, the diving duck, Baer’s Pochard (Aythya baeri) was widely distributed in East and South Asia, but according to a recent estimate, its global population is now less than 1000 individuals. To date, the mitochondrial genome of A. baeri has not been deposited and is not available in GenBank. Therefore, we aimed to sequence the complete mitochondrial genome of this species. The genome was 16,623 bp in length, double stranded, circular in shape, and contained 13 protein-coding genes, 22 tRNA genes, two rRNA genes, and one non-coding control region. Many structural and compositional similarities were discovered between A. baeri and the other three Aythya mitochondrial genomes. Among 13 protein-coding genes of the four Aythya species, the fastest-evolving gene was ATP8 while the slowest-evolving gene was COII. Furthermore, the phylogenetic tree of Anatidae based on Bayesian inference and maximum likelihood methods showed that the relationships among 15 genera of the Anatidae family were as follows: Dendrocygna was an early diverging lineage that was fairly distant from the other ingroup taxa; Cygnus, Branta, and Anser were clustered into one branch that corresponded to the Anserinae subfamily; and Aythya, Asarcornis, Netta, Anas, Mareca, Mergus, Lophodytes, Bucephala, Tadorna, Cairina, and Aix were clustered into another branch that corresponded to the Anatinae subfamily. Our target species and three other Aythya species formed a monophyletic group. These results provide new mitogenomic information to support further phylogenetic and taxonomic studies and genetic conservation of Anatidae species.

Highlights

The diving duck, Baer’s Pochard (Aythya baeri) was widely distributed in East and South Asia, but according to a recent estimate, its global population is less than 1000 individuals
Among the abovementioned genes in most birds, one protein-coding genes (PCGs) (ND6) and eight transfer RNA (tRNA) genes are located on the L-strand, whereas the control regions (CR) and the remaining 28 genes are located on the H-strand[5,6]
After a sharp decline in its population, it was classified as Endangered by the International Union for Conservation of Nature (IUCN), after which its conservation level increased to Critically Endangered in 2 01218

Summary

Introduction

The diving duck, Baer’s Pochard (Aythya baeri) was widely distributed in East and South Asia, but according to a recent estimate, its global population is less than 1000 individuals. The mitochondrial genome (mitogenome) is a circular, double-stranded molecule with a closed structure It usually has a length of ~ 16 kb and is made up of a heavy strand (H-strand) and a light strand (L-strand) containing a total of 37 genes: 13 protein-coding genes (PCGs), two ribosomal RNA genes (rRNAs), and 22 transfer RNA (tRNA) g enes[2,3]. Baer’s Pochard (Aythya baeri) is a diving duck that belongs to the order Anseriformes, subfamily Anatinae, family Anatidae It was distributed in the Amur and Ussuri River basins of far eastern Russia and northeastern China during the breeding season and in eastern and southern China, India, Bangladesh, and Myanmar following migration in winter[16]. The results could serve as a foundation for phylogenetic study as well as molecular biological data for taxonomic research on Anatidae species

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