CHROMOSOME-SPECIFIC ORGANIZATION OF HUMAN ALPHA SATELLITE DNA

  • 1 January 1985
    • journal article
    • research article
    • Vol. 37  (3) , 524-532
Abstract
Restriction endonuclease analysis of human genomic DNA previously revealed several prominent repeated DNA families defined by regularly spaced enzyme recognition sites. One of these families, termed .alpha. satellite DNA, was originally identified as tandemly repeated 340- or 680-base pair (bp) EcoRI fragments that hybridize to the centromeric regions of human chromosomes. The molecular organization of .alpha. satellite DNA was investigated on individual human chromosomes by filter hybridization and in situ hybridization analysis of human DNA and DNA from rodent/human somatic cell hybrids, each containing only a single human chromosome. As probes, a cloned 340-bp EcoRI .alpha. satellite fragment and a cloned .alpha. satellite-containing 2.0-kilobase pair (kpb) BamHI fragment from the pericentromeric region of the human X chromosome were used. In each somatic cell hybrid DNA, the 2 probes hybridized to a distinct subset of DNA fragments detected in total human genomic DNA. .alpha. Satellite DNA on each of the human chromosomes examined-the X and Y chromosomes and autosomes 3, 4 and 21 is organized in a specific and limited number of molecular domains. Subsets of .alpha. satellite DNA on individual chromosomes differ from one another, both with respect to restriction enzyme periodicities and with respect to their degree of sequence relatedness. Some, and perhaps many, human chromosomes may be characterized by a specific organization of .alpha. satellite DNA at their centromeres and that, under appropriate experimental conditions, cloned representatives of .alpha. satellite subfamilies may serve as a new class of chromosome-specific DNA markers.