Centromeric alphoid DNA heteromorphisms of chromosome 21 revealed by FISH-technique

The centromeric heterochromatin of chromosome 21 has been evaluated by the fluorescence in situ hybridization (FISH) technique. It was found that the alphoid DNA sequences of pericentromeric regions of chromosome 21 were highly heteromorphic when a centromeric specific probe was hybridized to these...

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Bibliographic Details
Published in:Clinical genetics 1997-02, Vol.51 (2), p.91-93
Main Authors: Verma, Ram S., Batish, Sat Dev, Gogineni, Swarna K., Kleyman, Svetlana M., Stetka, Daniel G.
Format: Article
Language:English
Subjects:
alphoid satellite DNA
Biological and medical sciences
Centromere - genetics
Chromatin - genetics
chromosome 21
Chromosome aberrations
Chromosomes, Human, Pair 21
Down Syndrome - genetics
Genetic Variation
Genetics, Population
hetaromorphisms
Humans
In Situ Hybridization, Fluorescence - methods
Medical genetics
Medical sciences
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Summary:The centromeric heterochromatin of chromosome 21 has been evaluated by the fluorescence in situ hybridization (FISH) technique. It was found that the alphoid DNA sequences of pericentromeric regions of chromosome 21 were highly heteromorphic when a centromeric specific probe was hybridized to these sequences. The variations were so extreme that they could even be arbitrarily classified into at least five sizes by comparison with the length of the short arm (p) of chromosome 18. They are: negative (1); small (2); medium (3); large (4); and very large (5). We used 15 normal cases and 12 individuals with trisomy 21 (Down syndrome), and the incidences for these five classes were 3.0%, 22.7%, 59.2%), 13.6% and 1.5%, respectively. At least 3% of the chromosomes no. 21 did not show any trace of hybridization signals, which apparently escape detection at interphase level as well. Although, the variations observed in the present study are continuous, the proposed classification may yield some implications for future investigations.
ISSN:0009-9163
1399-0004
DOI:10.1111/j.1399-0004.1997.tb02426.x