Telomere dataset used for calculating bulk and chromosome specific telomere length

Short telomeres cause age-related disease and long telomeres predispose to cancer; however, the mechanisms regulating telomere length are unclear. To probe these mechanisms,  we developed a nanopore sequencing method, Telomere Profiling, that identified mean telomere length to similar a Southern and to the clinical FlowFISH assay.  We mapped telomere reads to specific chromosome ends and, strikingly, could identify chromosome end-specific lengths that differed by more than 6kb.  We measured chromosome end-specific telomere lengths for 147 individuals and found that specific chromosome ends were consistently shorter or longer. This rank order of specific chromosome end telomere lengths was also found in newborn cord blood, suggesting telomere length is determined at birth. The average telomere length at birth was ~8kb +/- 250 bp, shorter than previously estimated. Understanding the mechanisms regulating length will allow deeper insights into telomere biology that can lead to new approaches to disease.

Methods
Telomeres were isolated and measured using telomere profiling protocol with Oxford Nanopore's MinION instrument and basecalled using ONT's guppy basecaller.