Mapping of 13 horse genes by fluorescence in-situ hybridization (FISH) andsomatic cell hybrid analysis

We report fluorescence in-situ hybridization (FISH) and somatic cell hybrid mapping data for 13 different horse genes (ANP, CD2, CLU, CRISP3, CYP17, F GG, IL1RN, IL10, MMP13, PRM1, PTGS2, TNFA and TP53). Primers for PCR amplif ication of intronic or untranslated regions were designed from horse-specif ic DNA or mRNA sequences in GenBank. Two different horse bacterial artifici al chromosome (BAC) libraries were screened with PCR for clones containing these 13 Type I loci, nine of which were found in the libraries. BAC clones were used as probes in dual colour FISH to confirm their precise chromosom al origin. The remaining four genes were mapped in a somatic cell hybrid pa nel. All chromosomal assignments except one were in agreement with human-ho rse ZOO-FISH data and revealed new and more detailed information on the equ ine comparative map. CLU was mapped by synteny to ECA2 while human-horse ZO O-FISH data predicted that CLU would be located on ECA9. The assignment of IL1RN permitted analysis of gene order conservation between HSA2 and ECA15, which identified that an event of inversion had occurred during the evolut ion of these two homologous chromosomes.