A chromosome 14-specific human satellite III DNA subfamily that shows variable presence on different chromosomes 14.

We describe a new subfamily of satellite III DNA (pTRS-63), which, by a combination of in situ hybridization to human metaphase chromosomes and analysis of a panel of somatic cell hybrids, is shown to be specific for human chromosome 14. This DNA has a basic 5-bp repeating unit of diverged GGAAT which is tandemly repeated and organized into either one of two distinct higher-order structures of 5 kb (designated the "L" form) or 4.8 kb (designated the "S" form). In addition, a third (Z) form, representing no detectable levels of this satellite III subfamily, is found. Results from five somatic cell hybrid lines and from a number of informative human individuals suggest that, on any one chromosome 14, only one of the three forms may exist. Subchromosomally, this sequence has been mapped to the p11 region and is distal to the domain occupied by another previously described satellite III subfamily (pTRS-47) found on chromosome 14. The pTRS-63 sequence described adds to the understanding of the structural organization of the short arm of human chromosome 14 and should be useful for the investigation of the molecular etiology of the frequently occurring t(13q14q) and t(14q21q) Robertsonian translocations.