Cryptic variants of acrocentric human chromosomes as analysed by restriction endonucleases

Ten phenotypically normal human individuals have been analysed by in situ treatments with restriction endonucleases in order to obtain a better characterization of some cryptic variants of acrocentric chromosomes. Treatments with AluI, NdeII and Sau 3AI confirm the existence of two cryptic amplified regions on the short arms of both one chromosome 15 and one chromosome 22, in one female. These amplifications seem to be of different origin involving the nucleolar organizer region of chromosome 15 and the satellite of chromosome 22.