DNA-fish method for measurement of telomere length

A method for determining chromosomal arm specific telomere length, comprising:

• a) immobilizing onto a substrate at least one sample of genomic DNA and a plurality of telomere length standards of different lengths;
• b) contacting the immobilized genomic DNA and telomere length standards of step a) with a first fluorescently labeled probe having a sequence complementary to a telomere sequence and a second fluorescently labeled probe having a sequence complementary to a unique subtelomeric sequence of a specific chromosomal arm under conditions such that said probes hybridize specifically to telomeric DNA and the unique subtelomeric DNA;
• c) detecting hybridized probes with a fluorescent microscopy image system, thereby generating digitized images of the hybridized probes;
• d) analyzing the digitized images to identify telomere spots that are marked by subtelomeric probe fluorescent signal and measure the fluorescent intensity of each marked telomere spot;
• e) generating a standard curve of telomere length in base-pair versus spot fluorescent intensities based on the plurality of telomere length standards on the substrate;
• and
• f) determining base-pair length of each marked telomere molecule (spot) by converting fluorescent intensity of telomere spot into base-pair length using a statistic mode against standard curve.