On Nov. 30, 1987, scientists at the University of California at San Diego and Wills Eye Hospital announced the cloning of the human retinoblastoma (Rb) gene. Rb is a tumor-suppressor gene associated with the pediatric eye cancer retinoblastoma.

This technique might be extended to other types of common mutations if these exist. Panels of mutation probes could then supplement restriction fragment length polymorphism analysis in retinoblastoma pedigrees, since RB gene mutations would be detected directly rather than by linkage.

Probe p6NRO.5 also detects a useful two-allele restriction fragment length polymorphism, so patients without DNA rearrangements in this region have a 50% chance of being heterozygous and informative for pedigree analysis.