title: Fixed nucleotide differences on the Y chromosome indicate clear divergence between Equus przewalskii and Equus caballus.
abstract: The phylogenetic relationship between Equus przewalskii and E. caballus is often a matter of debate. Although these taxa have different chromosome numbers, they do not form monophyletic clades in a phylogenetic tree based on mtDNA sequences. Here we report sequence variation from five newly identified Y chromosome regions of the horse. Two fixed nucleotide differences on the Y chromosome clearly display Przewalski's horse and domestic horse as sister taxa. At both positions the Przewalski's horse haplotype shows the ancestral state, in common with the members of the zebra/ass lineage. We discuss the factors that may have led to the differences in mtDNA and Y-chromosomal observations.
authors.affiliation: Institut für Tierzucht und Genetik, Veterinärmedizinische Universität Wien, Veterinärplatz, Wien, Austria. wallner@i122server.vu-wien.ac.at
authors.forename: B
authors.initials: B
authors.lastname: Wallner
authors.forename: G
authors.initials: G
authors.lastname: Brem
authors.forename: M
authors.initials: M
authors.lastname: Müller
authors.forename: R
authors.initials: R
authors.lastname: Achmann
mesh_terms: D000818:Animals; D001483:Base Sequence; D004272:DNA, Mitochondrial / Q000235:genetics; D014644:Genetic Variation / Q000235:genetics*; D006736:Horses / Q000145:classification / Q000235:genetics*; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D011336:Probability; D013045:Species Specificity; D014998:Y Chromosome / Q000235:genetics*
chemical_list: D004272:DNA, Mitochondrial