Comparative Chromosome Mapping of Musk Ox and the X Chromosome among Some Bovidae Species.

Proskuryakova Proskuryakova,Graphodatsky Graphodatsky,Bush Bush,Roelke-Parker Roelke-Parker,Kulemzina Kulemzina,O’brien O’Brien,Yudkin Yudkin,Farré Farré,Lemskaya Lemskaya,Kirillin Kirillin,Larkin Larkin,Perelman Perelman,Okhlopkov Okhlopkov

doi:10.3390/genes10110857

Abstract

Bovidae, the largest family in Pecora infraorder, are characterized by a striking variability in diploid number of chromosomes between species and among individuals within a species. The bovid X chromosome is also remarkably variable, with several morphological types in the family. Here we built a detailed chromosome map of musk ox (Ovibos moschatus), a relic species originating from Pleistocene megafauna, with dromedary and human probes using chromosome painting. We trace chromosomal rearrangements during Bovidae evolution by comparing species already studied by chromosome painting. The musk ox karyotype differs from the ancestral pecoran karyotype by six fusions, one fission, and three inversions. We discuss changes in pecoran ancestral karyotype in the light of new painting data. Variations in the X chromosome structure of four bovid species nilgai bull (Boselaphus tragocamelus), saola (Pseudoryx nghetinhensis), gaur (Bos gaurus), and Kirk’s Dikdik (Madoqua kirkii) were further analyzed using 26 cattle BAC-clones. We found the duplication on the X in saola. We show main rearrangements leading to the formation of four types of bovid X: Bovinae type with derived cattle subtype formed by centromere reposition and Antilopinae type with Caprini subtype formed by inversion in XSB1.

Highlights

Cetartiodactyla is a large mammalian order, including camels, whales, pigs, hippos, and ruminants—the suborder of animals with divided stomach
We extend the list of 18 species studied by detailed X chromosome bacterial artificial chromosome (BAC) mapping to include species from three tribes: nilgai bull (Boselaphini), saola, gaur (Bovini), and Kirk’s Dikdik (Antilopini) to reveal intrachromosomal rearrangements that occurred on the X chromosome in Bovidae family
The fundamental number of autosomal arms in musk ox is 58, which in general is characteristic for karyotypes of the Bovidae family [18]

Summary

Introduction

Cetartiodactyla is a large mammalian order, including camels, whales, pigs, hippos, and ruminants—the suborder of animals with divided stomach. Bovids include several domesticated species (cattle, goat, and sheep) with high economic significance. Accumulated cytogenetic data for the Bovidae family allow tracing the trends in evolution of karyotypes of the Bovinae [4,5,6,7] and Antilopinae [7,8,9,10,11] subfamilies. Some 43 bovid species have been studied by comparative chromosome painting, mostly with cattle painting probes [14]. Due to its economic importance, the cattle genome has been widely studied, identifying interchromosome rearrangements between species but resolving few intrachromosomal rearrangements. Because large chromosomal rearrangements by and large correspond in a parsimony sense to morphology-based phylogenies for the group, it seems that chromosomal rearrangements played an important role in the speciation of the Bovidae family [12]

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Discussion

Conclusion