DETERMINATION AND REGIONAL ASSIGNMENT OF GROUPED SETS OF MICROCLONES IN CHROMOSOME 1PTER-P35

In an approach to mapping physically the most distal 30 Mb of human ch romosome Ip, region-specific clone libraries were generated by microdi ssection and microcloning. PFGE blot hybridization of single or low-co py microclones against rare-cutter digests of genomic DNA revealed phy sical linkage for groups of markers. Supplementary PFGE analysis of 31 1p36-p35-specific probes for genetically mapped loci established a to tal of 15 grouped sets, consisting of altogether 69 markers. Twelve of the grouped sets were located in 1pter-p36.12, as revealed by microce ll hybrid mapping; the remaining three were localized proximal to 1p36 .12. Regional assignment and ordering of most grouped sets was achieve d either by evaluating the included genetic markers or by fluorescence in situ hybridization of representative probes. The genomic extent of individual grouped sets encompassed between 1100 and 2100 kb, coverin g a total of approximately 22 Mb of the distal chromosome 1p region. O ne particular grouped set was shown to contain seven polymorphic marke r loci that were previously suggested to be distributed across the ent ire 1pter-p35 region. The increase in the number of hybridization mark er probes in 1p36 and their physical mapping is expected to facilitate positional cloning experiments in this region; in particular, the con struction of clone contigs may be greatly facilitated. (C) 1995 Academ ic Press, Inc.