LARGE-SCALE ISOLATION OF HUMAN 1P36-SPECIFIC P1 CLONES AND THEIR USE FOR FLUORESCENCE IN-SITU HYBRIDIZATION

A series of 80 microclone probes derived from the chromosomal region 1 p36 was used to isolate corresponding clones from the ICRF human P1 li brary (see Francis et al., this issue). Hybridization screenings were performed using probe pools on high-density filter grids. A total of 8 7 P1 clones specific for 1p36 were isolated. This large-scale approach allowed a detailed evaluation of the complexity, quality, and utility of this library. The isolated P1 clones were used both for size deter mination by pulsed-field gel electrophoresis and as probes for fluores cence in situ hybridization (FISH) analysis. FISH of P1 clones is show n to be both easy and efficient to perform on metaphase chromosomes an d interphase nuclei. This observation is expected to reveal new avenue s for diagnosis of disease-related chromosomal changes. The use of P1 clones as a tool in clinical and tumor interphase cytogenetics is disc ussed and compared with FISH data of other long insert clones such as cosmids and YAC clones.