Exceptional conservation of horse-human gene order on X chromosome revealed by high-resolution radiation hybrid mapping

Terje Raudsepp, Eun Joon Lee, Srinivas R. Kata, Candice Brinkmeyer, James R. Mickelson, Loren C. Skow, James E. Womack, Bhanu P. Chowdhary

Research output: Contribution to journalArticlepeer-review

61 Citations (Scopus)


Development of a dense map of the horse genome is key to efforts aimed at identifying genes controlling health, reproduction, and performance. We herein report a high-resolution gene map of the horse (Equus caballus) X chromosome (ECAX) generated by developing and typing 116 gene-specific and 12 short tandem repeat markers on the 5,000-rad horse x hamster whole-genome radiation hybrid panel and mapping 29 gene loci by fluorescence in situ hybridization. The human X chromosome sequence was used as a template to select genes at 1-Mb intervals to develop equine orthologs. Coupled with our previous data, the new map comprises a total of 175 markers (139 genes and 36 short tandem repeats, of which 53 are fluorescence in situ hybridization mapped) distributed on average at ≈880-kb intervals along the chromosome. This is the densest and most uniformly distributed chromosomal map presently available in any mammalian species other than humans and rodents. Comparison of the horse and human X chromosome maps shows remarkable conservation of gene order along the entire span of the chromosomes, including the location of the centromere. An overview of the status of the horse map in relation to mouse, livestock, and companion animal species is also provided. The map will be instrumental for analysis of X linked health and fertility traits in horses by facilitating identification of targeted chromosomal regions for isolation of polymorphic markers, building bacterial artificial chromosome contigs, or sequencing.

Original languageEnglish
Pages (from-to)2386-2391
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number8
Publication statusPublished - Feb 22 2004
Externally publishedYes


  • Comparative map
  • Gene mapping
  • Mouse

ASJC Scopus subject areas

  • General


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