An ordered BAC contig map of the equine major histocompatibility complexGustafson A.L.a · Tallmadge R.L.b · Ramlachan N.a · Miller D.b · Bird H.b · Antczak D.F.b · Raudsepp T.a · Chowdhary B.P.a · Skow L.C.a
aDepartment of Veterinary Anatomy and Public Health, College of Veterinary Medicine, Texas A&M University, College Station, TX; bJames A. Baker Institute for Animal Health, Cornell University, Ithaca, NY (USA)
A physical map of ordered bacterial artificial chromosome (BAC) clones was constructed to determine the genetic organization of the horse major histocompatibility complex. Human, cattle, pig, mouse, and rat MHC gene sequences were compared to identify highly conserved regions which served as source templates for the design of overgo primers. Thirty-five overgo probes were designed from 24 genes and used for hybridization screening of the equine USDA CHORI 241 BAC library. Two hundred thirty-eight BAC clones were assembled into two contigs spanning the horse MHC region. The first contig contains the MHC class II region and was reduced to a minimum tiling path of nine BAC clones that span approximately 800 kb and contain at least 20 genes. A minimum tiling path of a second contig containing the class III/I region is comprised of 14 BAC clones that span approximately 1.6 Mb and contain at least 34 genes. Fluorescence in situ hybridization (FISH) using representative clones from each of the three regions of the MHC localized the contigs onto ECA20q21 and oriented the regions relative to one another and the centromere. Dual-colored FISH revealed that the class I region is proximal to the centromere, the class II region is distal, and the class III region is located between class I and II. These data indicate that the equine MHC is a single gene-dense region similar in structure and organization to the human MHC and is not disrupted as in ruminants and pigs.
© 2003 S. Karger AG, Basel
Request reprints from Dr. Loren Skow
Department of Veterinary Anatomy and Public Health
College of Veterinary Medicine, Texas A&M University
College Station, Texas 77843-4458 (USA);
telephone: +1 979-845-3194; fax: +1 979-845-9972
A.L.G. and R.L.T. contributed equally to this work.
Funded by grant support to B.P. Chowdhary and L.C. Skow from the Texas Higher Education Coordinating Board Advanced Research Program, the Link Endowment for Equine Research, and the Texas Equine Research Fund and to D.F. Antczak from NIH grant HD-34086, the Harry M. Zweig Memorial Fund for Equine Research, the Dorothy Russell Havemeyer Foundation, Inc., the USDA Regional Grant Program, and the Morris Animal Foundation.
Received 31 May 2003;
manuscript accepted 30 July 2003.
Number of Print Pages : 7
Number of Figures : 2, Number of Tables : 2, Number of References : 50
Cytogenetic and Genome Research
Formerly ‘Cytogenetics and Cell Genetics’
Vol. 102, No. 1-4, Year 2003 (Cover Date: 2003)
Journal Editor: H.P. Klinger, Bronx, N.Y.; M. Schmid, Würzburg
ISSN: 1424–8581 (print), 1424–859X (Online)
For additional information: http://www.karger.com/journals/cgr