SHORT COMMUNICATION Radiation hybrid comparative mapping between human chromosome 17 and porcine chromosome 12 demonstrates conservation of gene order X.-W. Shi* ,² , C. J. Fitzsimmons*, C. Gene Ãt ³ , R. Prather § , K. Whitworth § , J. A. Green § and C. K. Tuggle* *Department of Animal Science, Iowa State University, Ames, IA 50011, USA. ² Laboratory of Cellular and Molecular Evolution, Kunming Institute of Zoology, CAS, Kunming 650223, China. ³ INRA, Laboratoire de Genetique Cellulaire, 31326 Castanet-Tolosan, France. § Department of Animal Science, University of Missouri-Columbia, Columbia, MO 65211, USA Summary A comparative study of human chromosome 17 (HSA17) and pig chromosome 12 (SSC12) was conducted using both somatic cell hybrid panel (SCHP) and radiation hybrid (RH) panel analysis. Sequences from an expressed sequence tag (EST) project in pig reproduction were examined and six genes and ESTs originally believed to map to HSA17 were selected for this study. The genes/ESTs were TATA box binding protein- associated factor (TAF2N/RBP56), a-2-plasmin inhibitor (SERPINF2/PLI), H3 histone family 3B (H3F3B), aminopeptidase puromycin sensitive (NPEPPS), an expressed sequence tag (ESTMI015) and P311 protein (P311). The SCHP analysis mapped ®ve genes/ESTs (TAF2N, H3F3B, SERPINF2, NPEPPS and ESTMI015) to SSC12q11-q15 and SSC12p11-p15 with 100% concordance, and assigned P311 to SSC2 (1/2q24)-q29 with 100% concordance. Radiation hybrid analysis of all six genes con®rmed the SCHP mapping results, with average retention frequency of 25%. Recent human sequence data demonstrated that P311 is actually located on HSA5q. As HSA5q and SSC2q show conserved syntenic regions predicted from bi-directional painting, our P311 mapping data is consistent with these results. An expanded comparative SSC12 RH map integrating the ®ve new type I markers and 23 previously mapped loci was established using a LOD score threshold of 4.8. The gene order of the ®ve genes/ESTs on the SSC12 framework RH map (H3F3B±ESTMI015±NPEPPS± TAF2N±SERPINF2) is identical to the HSA17 GB4 map but with inversion of the map as conventionally drawn. Keywords comparative map, HSA17, SSC12, pig, radiation hybrid mapping. Comparative mapping is expected to be an ef®cient and powerful strategy in predicting gene location from the well- developed human genome map, and as a method for selecting candidate genes for improvement of economically important traits in livestock species. Bi-directional painting has revealed 37 synteny groups conserved between the pig and human (Goureau et al. 1996). However, even within conserved synteny groups, re-arrangement of gene order and distance discrepancy of adjacent loci have been docu- mented (Archibald et al. 1995; Sun et al. 1999; Van Poucke et al. 1999). Accumulation of comparative mapping infor- mation between human and swine is helpful for under- standing the evolutionary relationship between the two genomes and in predicting gene order and location with increased certainty. A total of 128 linkage groups covering all porcine chromosomes (n  19) were established in a ®rst-generation porcine whole-genome radiation hybrid (WG-RH) analysis (Hawken et al. 1999). This useful map Address for correspondence C.K. Tuggle, Department of Animal Science, Iowa State University, Ames, IA 50011, USA. E-mail: cktuggle@iastate.edu Accepted for publication 7 April 2001 Ó 2001 International Society for Animal Genetics, Animal Genetics, 32, 205±209