A full set of 24 chromosome-specific probes to analyze single cells or cell organelles to test for abnormalities is described. When used in an assay based on sequential hybridization, the full set is comprised of three subsets of chromosome-specific probes with each set comprised of 8 different probes. Also described are assays using a set of probes to analyze single cells and cellular organelles to accurately determine the number and type of targeted human chromosomes in various types of cells and cell organelles, such as tumor cells, interphase cells and first polar bodies biopsied from non-inseminated oocytes. Methods of selection or generation of suitable probes and hybridization protocols are described, as are preferred probes for frill set of 24 chromosome-specific probes to target all 24 human chromosomes are described in the Tables.
STATEMENT OF GOVERNMENTAL SUPPORT
 This invention was made during work supported by U.S. Department of Energy under Contract No. DE-AC03-76SF00098, now Contract No. DE-AC02-05CH11231. The government has certain rights in this invention.