TelOMpy enables single-molecule resolution of telomere length from optical genome mapping data

<h4>Background</h4>Existing methods for assessing telomere length suffer from various limitations, including low resolution, narrow scope, limited throughput, and poor reproducibility. These issues largely arise from the reliance on laborious and indirect approaches to telomere length measurement.<h4>Results</h4>We developed TelOMpy, a bioinformatics tool designed to determine the lengths of individual telomeres from optical genome mapping data. To demonstrate its capabilities, we applied TelOMpy to data from a Western diet mouse experiment, revealing substantial variation in individual telomere lengths and highlighting the impact of a high-fat diet on telomere shortening and loss. Utilizing a newly developed protocol for high-molecular-weight DNA extraction, we generated the first optical genome maps from sperm and compared telomere lengths between sperm and somatic tissues in overweight mice.<h4>Conclusions</h4>TelOMpy enables direct measurement of absolute telomere lengths at the single-molecule level across thousands of telomeres per sample. This approach eliminates errors associated with indirect methods and offers high analytical power and reproducibility, representing a significant advancement in telomere length analysis.