ADVANCES IN THE AUTOMATED DETECTION OF METAPHASE CHROMOSOMES LABELED WITH FLUORESCENCE DYES

Applications of fluorescence in situ hybridization (FISH) for transloc ation studies and biological dosimetry would benefit substantially fro m reliable and efficient automatic detection of metaphase chromosomes labeled with fluorescent dyes. We replicated and evaluated a fluoresce nce metaphase finder previously developed at the Medical Research Coun cil (MRC), Human Genetics Unit (Scotland) and at Lawrence Berkeley Lab oratory (LBL; California), The MRC/LBL system seemed to detect nearly all of the metaphases on the test slides, but it presented an unaccept able number of false positives (about five false positives per one tru e positive). Furthermore, we determined that the system actually overc alled true detections by counting certain metaphase spreads twice (dup licates), Through modifications of the MRC/LBL system, we developed th e Lawrence Livermore National Laboratory (LLNL) system, which minimize s the detection of duplicates, incorporates new detection features, us es a binary decision tree (BDT) for classification, and provides funct ionalities to improve scanning accuracy and improve the post-detection review. To test the new system, DAPI-stained preparations of metaphas e chromosomes from blood lymphocytes of four unrelated donors were pla ced on slides in drops ranging from 7 mm to 20 mm in diameter. Drops c ontained between 5 and 200 scorable metaphases each, The LLNL system a chieved similar to 90% detection of non-duplicated metaphases as verif ied by an expert cytogeneticist, with typically less than one false po sitive per every one true positive detected. (C) 1998 Wiley-Liss, Inc. dagger.