CONTIGUOUS ARRAYS OF SATELLITE-1, SATELLITE-3, AND SATELLITE-BETA FORM A 1.5-MB DOMAIN ON CHROMOSOME 22P

The centromeric heterochromatin of all the human chromosomes is compos ed of megabases of tandemly repeated satellite DNA, Some of these sequ ences have been implicated in centromere formation and/or segregation but the arrangement of most of them on a large scale remains largely u ncharacterized because of the difficulties in analyzing repetitive DNA . The alpha satellite is the best studied and is present in large tand em arrays at all centromeres, but satellites 1, 3, and beta have also been detected on a number of chromosomes. Here we have used FISH to ex tended DNA fibers to analyze these satellites on the short arm of the acrocentric chromosome 22. The satellite sequences were found to form a continuous domain spanning about 1.5 Mb and consisting of a major bl ock of satellite 1 flanked by two blocks of beta satellite and three b locks of satellite 3. These six blocks of satellite DNA appear to form contiguous arrays with little intervening DNA. (C) 1997 Academic Pres s.