A radiation hybrid map of the RN region in pigs demonstrates conserved gene order compared with the human and mouse genomes

We recently constructed a 7000-rad porcine whole-genome radiation hybrid (R H) panel with the primary objective of integrating linkage maps of microsat ellites with evolutionary conserved genes into one ordered map. In order to evaluate the resolution of this RH panel, we have now constructed a radiat ion hybrid map of the Chromosome (Chr) 15q2.3-q2.6 region containing the RN gene. This gene has large effects on glycogen content in muscle and meat q uality. Ten microsatellites covering a region of 55 centiMorgans and eight genes (AE3, FN1, IGFBP5, INHA, IRS1, PAX3, TNP1, and VIL1) were placed on t he Sscr15 RH map. All the genes, except IRS1, were mapped on the RH map bet ween microsatellites located in 15q2.5. The relative order of AE3 and INHA was inverted on the porcine physical map in comparison with the mouse linka ge map. The order of other genes already mapped in the mouse (FN1, IGFBP5, TNP1, VIL1, INHA/AE3, and PAX3) was identical in pigs. We found no clear di fference between the gene order on pig Chr 15 and human Chr 2q.