MAPPING OF GROWTH-HORMONE RELEASING HORMONE-RECEPTOR TO SWINE CHROMOSOME-18

The growth hormone releasing hormone receptor (GHRHR) was mapped in th e pig for study as a potential candidate gene in controlling pig quant itative growth and carcass characteristics. Primers were designed from the pig GHRHR sequence to amplify a 1.65-kb intronic fragment between exons 6 and 7. By using a pig-rodent somatic cell hybrid panel, GHRHR was mapped to pig chromosome 18 (SSC18) with 100% concordance, and th e regional assignment was SSC18q24 with 89% concordance. The polymeras e chain reaction-restriction fragment length polymorphisms (PCR-RFLPs) with MseI and TaqI were developed to confirm this assignment with lin kage analysis by using the European Pig Gene Mapping Project (PiGMaP) reference families. Pig GHRHR was mapped with strong linkage to SSC18 markers S0062 and S0120 (lod > 8). The GHRHR and IGFBP3 were found to map near to each other on human chromosome 7 (HSA7), and the pig IGFBP 3 gene has been mapped to SSC18 by others. Our mapping of pig GHRHR in creases the comparative information available on the SSC18 maps and fu rther confirms the synteny conservation between HSA7 and SSC18.