Alphoid DNA diversity of a so-called monocentric Robertsonian fusion.

The centromeric heterochromatin of a Robertsonian translocation with t(13q14q), thought to be monocentric by conventional staining methods, was found to be dicentric using molecular techniques. The breakpoints were confined within the alphoid DNA subfamilies and fusion resulted in a compound centromere. The fragile nature of alphoid DNA sequences during Robertsonian translocation has opened new avenues in understanding other chromosomal aberrations involving centric fusion.