The invention relates to the field of cytogenetics and the application of genetic diagnostic techniques in pathology and hematology. Specifically, the invention relates to nucleic acid probes that can be used in hybridization techniques for the detection of chromosomal aberrations and other gene rearrangements such as immunoglobulin and T-cell receptor gene rearrangements. The probes provided by the invention are a distinct and balanced set of probes of comparable size, each preferably being from 1 to 100 kb, or smaller, and flanking a potential breakpoint in a chromosome.