Marker chromosomes lacking {alpha}-satellite DNA: A new intriguing class of abnormalities
- Case Western Reserve Univ., Cleveland, OH (United States); and others
Recent studies have implicated {alpha}-satellite DNA as an integral part of the centromere and important for the normal segregation of chromosomes. We analyzed four supernumerary marker chromosomes in which fluorescence in situ hybridization (FISH) could detect neither pancentromeric or chromosome specific {alpha}-satellite DNA. Mosaicism of the markers existed, but each was present in the majority of cells indicating that they segregated normally. FISH with chromosome-specific libraries identified the origins of these markers as chromosomes 13 (1 case) and 15 (3 cases). High resolution analysis, combined with hybridization of a series of cosmid probes, revealed that each marker was a symmetrical duplication of the terminal long arm of the parent chromosome. Telomeric sequences were detected by FISH indicating linear structures. Breakpoint heterogeneity, as defined by cosmid probes, was demonstrated in the three cases involving chromosome 15. No pericentromeric satellite III DNA could be detected on three markers. Studies with anti-centromere antibodies are in progress to assay for centromeric antigens on the markers, as expected at functional centromeric sites. Our results demonstrate that the precise structural identification and heterogeneity of these markers can be easily elucidated using FISH with unique sequence cosmid probes. We conclude from our studies and others in the literature: (1) there is a newly defined class of markers lacking {alpha}-satellite DNA and containing duplications of terminal sequences; (2)neither {alpha}-satellite nor satellite III DNA at levels detectable by FISH is necessary for fidelity in the normal segregation of chromosomes; and (3) these markers were most likely formed by recombination of the long arms during meiosis.
- OSTI ID:
- 133413
- Report Number(s):
- CONF-941009-; ISSN 0002-9297; TRN: 95:005313-0141
- Journal Information:
- American Journal of Human Genetics, Vol. 55, Issue Suppl.3; Conference: 44. annual meeting of the American Society of Human Genetics, Montreal (Canada), 18-22 Oct 1994; Other Information: PBD: Sep 1994
- Country of Publication:
- United States
- Language:
- English
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