The 8% That Took 19 Years to Read: Completing the Human Genome
The 2003 Human Genome Project declared the genome essentially finished, but about 8% remained unread, concentrated in centromeres, telomeres, and segmental duplications. In 2022 the Telomere-to-Telomere (T2T-CHM13) assembly delivered a gapless genome (except Y) using long-read sequencing, revealing complete centromeres and new sequence, including immune-related gene families. But it's a single reference genome, not the full human variation; the next milestone is a population-scale pangenome.
