Telomere Probes
Telomeres are DNA-protein complexes that cap the ends of eukaryotic chromosomes. Every telomere contains 3 to 20 kb of tandem TTAGGG repeats. The telomere associated repeats (TAR), also known as the subtelomeric repeats, are immediately proximal to the TTAGGG repeats. They contain regions of shared homology between subsets of certain chromosomes.
Each TelVysion targeted site is a unique, chromosome specific DNA located approximately 100 to 300 kb from the chromosome end.
In the context of constitutional chromosome analysis, the most distal region of unique DNA on a chromosome arm commonly is referred to as the "subtelomere." Subtelomeres are known to contain a high concentration of genes as compared to other chromosome regions.Yet, subtelomere abnormalities can be difficult, if not impossible, to detect by routine G-band analysis because subtelomeres stain negative (light).
Each TelVysion targeted site is a unique, chromosome specific DNA located approximately 100 to 300 kb from the chromosome end.
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| Schematic of the make-up of human chromosome telomeric regions. Diagram courtesy of C. Lese and D. Ledbetter, University of Chicago. |
In the context of constitutional chromosome analysis, the most distal region of unique DNA on a chromosome arm commonly is referred to as the "subtelomere." Subtelomeres are known to contain a high concentration of genes as compared to other chromosome regions.Yet, subtelomere abnormalities can be difficult, if not impossible, to detect by routine G-band analysis because subtelomeres stain negative (light).