FISH analysis comparing genome organization in the domestic horse (Equus caballus) to that of the Mongolian wild horse (E. przewalskii)

Przewalski’s wild horse (E. przewalskii, EPR) has a diploid chromosome number of 2n = 66 while the domestic horse (E. caballus, ECA) has a diploid chromosome number of 2n = 64. Discussions about their phylogenetic relationship and taxonomic classification have hinged on comparisons of their skeletal morphology, protein and mitochondrial DNA similarities, their ability to produce fertile hybrid offspring, and on comparison of their chromosome morphology and banding patterns. Previous studies of GTG-banded karyotypes suggested that the chromosomes of both equids were homologous and the difference in chromosome number was due to a Robertsonian event involving two pairs of acrocentric chromosomes in EPR and one pair of metacentric chromosomes in ECA (ECA5). To determine which EPR chromosomes were homologous to ECA5 and to confirm the predicted chromosome homologies based on GTG banding, we constructed a comparative gene map between ECA and EPR by FISH mapping 46 domestic horse-derived BAC clones containing genes previously mapped to ECA chromosomes. The results indicated that all ECA and EPR chromosomes were homologous as predicted by GTG banding, but provide new information in that the EPR acrocentric chromosomes EPR23 and EPR24 were shown to be homologues of the ECA metacentric chromosome ECA5.

[1]  M. Houck,et al.  Chromosomes ofDamaliscus (Artiodactyla, Bovidae): Simple and complex centric fusion rearrangements , 1996, Chromosome Research.

[2]  H. Scherthan,et al.  Zoo-FISH delineates conserved chromosomal segments in horse and man , 1996, Chromosome Research.

[3]  O. Ryder,et al.  Immunological systematics of the extinct quagga (Equidae) , 1985, Experientia.

[4]  F. Piumi,et al.  Mapping of 31 horse genes in BACs by FISH , 2001, Chromosome Research.

[5]  Han N. Lim,et al.  A survey of equid mitochondrial DNA: Implications for the evolution, genetic diversity and conservation of Equus , 2000, Conservation Genetics.

[6]  N. Saitou,et al.  Mitochondrial DNA sequences of various species of the genus Equus with special reference to the phylogenetic relationship between Przewalskii's wild horse and domestic horse , 1995, Journal of Molecular Evolution.

[7]  F. Piumi,et al.  Horse v-fes feline sarcoma viral oncogene homologue; pyruvate kinase, muscle type 2; plasminogen; beta spectrin, non-erythrocytic 1; thymidylate synthetase; and microsatellite LEX078 map to 1q14-q15, 1q21, 31q12-q14, 15q22, 8q12-q14, and 14q27, respectively , 2004, Chromosome Research.

[8]  H. Ellegren,et al.  Mapping of 13 horse genes by fluorescence in-situ hybridization (FISH) and somatic cell hybrid analysis , 2004, Chromosome Research.

[9]  Gérard Guérin,et al.  The first-generation whole-genome radiation hybrid map in the horse identifies conserved segments in human and mouse genomes. , 2003, Genome research.

[10]  M A Ferguson-Smith,et al.  Reciprocal chromosome painting among human, aardvark, and elephant (superorder Afrotheria) reveals the likely eutherian ancestral karyotype , 2003, Proceedings of the National Academy of Sciences of the United States of America.

[11]  L. Skow,et al.  Conservation of gene order between horse and human X chromosomes as evidenced through radiation hybrid mapping. , 2003, Genomics.

[12]  F. Piumi,et al.  Mapping of equine potassium chloride co-transporter (SLC12A4) and amino acid transporter (SLC7A10) and preliminary studies on associations between SNPs from SLC12A4, SLC7A10 and SLC7A9 and osmotic fragility of erythrocytes. , 2002, Animal genetics.

[13]  A. Billault,et al.  Cytogenetic localization of 136 genes in the horse: comparative mapping with the human genome , 2002, Mammalian Genome.

[14]  P. Mäenpää,et al.  Protamine P1 sequences in equids: comparison with even-toed animals. , 2002, Theriogenology.

[15]  M. Hurles,et al.  Mitochondrial DNA and the origins of the domestic horse , 2002, Proceedings of the National Academy of Sciences of the United States of America.

[16]  E. G. Cothran,et al.  Rejection of MITF and MGF as the genes responsible for appaloosa coat colour patterns in horses. , 2002, Animal genetics.

[17]  B. Chowdhary,et al.  Comparative FISH mapping of 32 loci reveals new homologous regions between donkey and horse karyotypes , 2002, Cytogenetic and Genome Research.

[18]  Stephen J O'Brien,et al.  Evolution of mammalian genome organization inferred from comparative gene mapping , 2001, Genome Biology.

[19]  E. Cribiu,et al.  Isolation, characterization and FISH assignments of horse BAC clones containing type I and II markers , 2001, Cytogenetic and Genome Research.

[20]  V. Eisenmann,et al.  Extant and fossil Equus (Mammalia, Perissodactyla) skulls: a morphometric definition of the subgenus Equus , 2000 .

[21]  H. Endo,et al.  Morphological character of the shoulder and leg skeleton in Przewalski's horse (Equus przewalskii). , 1999, Annals of anatomy = Anatomischer Anzeiger : official organ of the Anatomische Gesellschaft.

[22]  O. Ryder,et al.  Mitochondrial control region and 12S rRNA variation in Przewalski's horse (Equus przewalskii). , 1998, Animal genetics.

[23]  J. Clegg,et al.  Phylogenetic Relationships Within the Genus Equus and the Evolution of α and θ Globin Genes , 1998, Journal of Molecular Evolution.

[24]  M. Świtoński,et al.  Studies of synaptonemal complexes in farm mammals--a review. , 1998, The Journal of heredity.

[25]  E. Cribiu,et al.  Construction of a horse BAC library and cytogenetical assignment of 20 type I and type II markers , 1998, Mammalian Genome.

[26]  O. Ryder.  Przewalski’s Horse: Prospects for Reintroduction into the Wild , 1993 .

[27]  O. Ryder,et al.  Genomic distribution of heterochromatic sequences in equids: implications to rapid chromosomal evolution. , 1991, The Journal of heredity.

[28]  M. Breen.  Chromosome studies in the Equidae. , 1990 .

[29]  O. Ryder,et al.  Genetic studies of blood markers in Przewalski's horses. , 1987, The Journal of heredity.

[30]  O. Ryder,et al.  Mitochondrial DNA evolution in the genus Equus. , 1986, Molecular biology and evolution.

[31]  M. Kaminski.  The biochemical evolution of the horse. , 1979, Comparative biochemistry and physiology. B, Comparative biochemistry.

[32]  K. Benirschke,et al.  Chromosome banding studies of the Equidae. , 1978, Cytogenetics and cell genetics.

[33]  R. Short,et al.  Meiosis in interspecific equine hybrids. II. The przewalski horse/domestic horse hybrid. , 1974, Cytogenetics and cell genetics.

[34]  K. Benirschke,et al.  Chromosome Complement: Differences between Equus caballus and Equus przewalskii, Poliakoff , 1965, Science.