The phylogenetic relationship of the muskox and takin based on high resolution, G-banded, chromosome analysis

M Pasitschniak-Arts,B Seidel,P F Flood,S M Schmutz,S Tedesco

doi:10.7557/2.12.3.1046

Abstract

Muskoxen, Ovibos moschatus, currently inhabit parts of the Canadian mainland tundra, numerous Arctic islands, regions of Alaska, Norway, Sweden, northern and eastern Greenland, and the Taymyr Peninsula (Lent, 1988). The takin, Budorcas taxicolor, is an Asian species presently found in mountainous areas of west central China, Burma, Bhutan and India Qia-Yan, 1989; Neas and Hoffman, 1987). Both species appear to have originated from a common ancestor in Asia and exhibit morphological similarities. Muskoxen apparently dispersed from north central Asia to North America during the Illinoian glaciation Qia-Yan, 1989). Both the muskox and the takin are members of the Bovidae. The species in this family often have markedly different diploid numbers of chromosomes, but the fundamental number (number of chromosome arms) differs only from 58 to 62 (Hsu and Benirschke, 1967-1977; Wurster and Benirschke, 1968). The consistency in the. number of chromosome arms suggests Robertsonian fusion, or the joining of chromosomes at their centromeres, to be a dominant phenomenon in the evolution of the Bovidae. The relationship of the muskox to other members in the Bovidae is somewhat unclear. Many related genera of bovids adapted to colder climates are now extinct, leaving only the muskox and takin (Jia-Yan, 1989; Lent, 1988; Neas and Hoffman, 1987). Despite the apparent close relatedness of the two species, banded karyotypes of the muskox and takin have yet to be compared. In the Bovidae, individual autosome pairs cannot be reliably distinguished using conventional staining (Lin et aL, 1977), but they have been identified using G-banding (Wang and Federoff, 1974) in a variety of species (Evans et ai, 1973; Lin et aL, 1977). High resolution or elongated banding techniques have further improved resolution and facilitated chromosome comparisons (Mensher et aL, 1989). The object of our research was to compare the individual chromosomes of the muskox and takin, and to determine the cytotaxonomic relationship of the two species using high resolution G-banding. Karyotypes were prepared from blood samples from three male muskoxen and two female takin: the muskoxen are part of

Highlights

Muskoxen, Ovibos moschatus, currently inhabit The relationship of the muskox to other parts of the Canadian mainland tundra, nume- members in the Bovidae is somewhat unclear
Muskoxen apparently dispersed from north cen- staining (Lin et aL, 1977), but they have been tral Asia to North America during the Illinoian identified using G-banding (Wang and Federoff, glaciation Qia-Yan, 1989)
Karyotypes were prepared somes at their centromeres, to be a dominant from blood samples from three male muskoxen phenomenon in the evolution of the Bovidae. and two female takin: the muskoxen are part of Rangifer, 12 (3), 1992 a captive research herd at the University of Sa- the corresponding acrocentrics of the takin, skatchewan (Flood et al, 1984), and the takin many of these chromosomes were found to are kept at Tierpark Berlin-Friedrichsfelde, Ger- have homologous banding patterns

Summary

Introduction

Ovibos moschatus, currently inhabit The relationship of the muskox to other parts of the Canadian mainland tundra, nume- members in the Bovidae is somewhat unclear. The takin, muskox and takin (Jia-Yan, 1989; Lent, 1988; Budorcas taxicolor, is an Asian species presently Neas and Hoffman, 1987). 1974) in a variety of species (Evans et ai, 1973; Both the muskox and the takin are members Lin et aL, 1977).

Results

Conclusion