Fluorescence spectroscopic detection and measurement of single telomere molecules

Telomeres are the end-caps of chromosomes that serve to protect the integrity of the genome. Below certain critical lengths, the telomeres can no longer fulfill their protective function, and chromosomal instability ensues. Telomeres shorten during normal cell division due to the end replication problem and are implicated in the development of various aging-associated diseases, including cancer. Telomere length has the potential to serve as a useful biomarker in the field of aging and cancer. However, existing methods of telomere measurement are either too laborious, unable to provide absolute measurement of individual telomere lengths, or limited to certain chromosomes or cell types. Here, we describe an easy single-molecule, fluorescence spectroscopic method for measuring the length of telomeres that permits the profiling of absolute telomere lengths in any DNA sample. We have demonstrated the accurate detection of telomeres as short as 100 bp using cloned telomere standards, and have profiled telomere lengths in human cancer cell lines and primary cells. Since this method allows direct comparison between samples, it could greatly improve the clinical utility of telomere biomarkers.