Chronicles at the edges of chromosomes: how to read the history of every telomere
At the end of every chromosome sits a cap made of repeating DNA letters: the telomere. For a long time it was measured as an average length across all chromosomes, as if judging a library by the average thickness of its books. But in humans, three ends, 17p, 20q, and 12p, are consistently shorter than the rest, and they are the ones more often linked to genome damage.