High-resolution physical mapping of human 5q31-q33 using three methods: radiation hybrid mapping, interphase fluorescence in situ hybridization, and pulsed-field gel electrophoresis.

Abstract

Three physical mapping methods, radiation hybrid (RH) mapping, pulsed-field gel electrophoresis (PFGE), and fluorescence in situ hybridization (FISH) of interphase nuclei, were used to determine the order and relative distances between 12 loci in the q31-q33 region of human chromosome 5. The information obtained by each of the methods was compared to determine whether they gave consistent results. Based upon a combination of data, the predicted order of the 12 loci is cen-ADRB2-PDEA-CSF1R-RPS14-ANX6-SPARC++ +-GLRA1-GLUR1-ADRA1B-IL12- GABRG2-GABRA1-tel. Over the 5-Mb region spanned by these loci, we determined that an RH mapping unit (centiray, cR6500) is equivalent to 21 kb, in good agreement with previous estimates of 27-34 kb/cR6500 using the same set of radiation hybrids to map other regions. Of the three methods, RH mapping was by far the easiest and most efficient method for determining both order and distances. In addition, the range of resolution of RH mapping was the broadest, ranging from approximately 200 kb to several megabasepairs. Interphase FISH was the most informative method for clarifying the order of closely linked markers. The FISH distances obtained in this study will be useful as an internal reference for high-resolution mapping studies of other regions on the long arm of human chromosome 5. In contrast to RH mapping and FISH, PFGE was the least reliable of the three methods, producing some data that were inconsistent with the distances determined by the other two methods.