Tracking of wisent–bison–yak mitochondrial evolution

Joanna Zeyland,Łukasz Wolko,Ryszard Słomski,Agnieszka Nowak,Daniel Lipiński,Jan Bocianowski,Anna Woźniak,Marlena Szalata

doi:10.1007/s13353-012-0090-4

Abstract

One of the most informative sources which allow the drawing of far-reaching conclusions about the origins and phylogenetics of many species, including domestic animals and humans, is mitochondrial DNA (mtDNA). One of the important research targets should include the identification of similarities between wild and domestic species. The analysis involved the nucleotide sequences of mtDNA of wisent, auroch, bison, yak, bovine reference sequence (BRS) T3, T3a, T3b, T1, T1a, T1’2’3, T2, T3, T4, T5, Q, Q1, P, R, I1, and I2 bovine haplotypes. The non-coding D-loop regions were excluded from the evolutionary analysis and 15,419-bp coding sequences were used in the final dataset. Trees constructed on the basis of whole mitochondrial genomes or on total mtDNA coding sequences alignment were generally in agreement with previous studies on the Bovini tribe. American bison shows stronger maternal relationships to yak than to wisent. It seems that the isolation and divergence of wisent took place early, almost 2 to 1.6 million years ago. This appears to be compatible with the paleontological date, indicating Late Pleistocene speciation of Bison bonasus. The yak/bison mitochondrial transfer model is in agreement with our mutation analysis and phylogenetic tree. The bison/yak mutations were collected in the bison mitochondrial genome before the transfer. After the transfer, the parallel accumulation of unique mutations took place. According to our assessment, the transfer took place at about 700 ky. The characteristic feature of the wisent and bison evolution is the maintenance of mtDNA variability, despite the fact that both species underwent population bottlenecks. Our studies did not reveal any impact of these phenomena populations in the analyzed mitochondrial genomes.Electronic supplementary materialThe online version of this article (doi:10.1007/s13353-012-0090-4) contains supplementary material, which is available to authorized users.

Highlights

The purpose of molecular phylogenetic analysis is to reconstruct evolutionary events on the basis of the analysis of nucleotide or amino acid sequences
One of the most informative sources which allow the drawing of far-reaching conclusions about the origins and phylogenetics of many species, including domestic animals and humans, is mitochondrial DNA
We present the complete mitochondrial genome of wisent (NC_014044) (Bison bonasus) and use it to reconstruct the phylogenetic relationships between wisent (European Bison), bison (Bison bison), and yak (Bos grunniens)

Summary

Introduction

The purpose of molecular phylogenetic analysis is to reconstruct evolutionary events on the basis of the analysis of nucleotide or amino acid sequences. Variants of mtDNA are inherited as a whole and the accumulation of mutations is the only source of variability. Due to the mentioned mtDNA properties, an evolutionary analysis is easier, as it allows the treatment of a set of polymorphic sites in mtDNA, i.e., its haplotype, as an entity. This provides the basis for the possibility of assessment of the time when a given new type, race, or species became. Mammalian mtDNA is characterized by a lack of introns, presence of one copy of orthologic genes, absence of recombination events, and a high level of mutations (Pesole et al 1999)

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Conclusion