Researchers have sequenced the entire human genome using Oxford Nanopore technology

A group of researchers, who make up the Telomere-to-Telomere (T2T) Consortium has published the first truly complete 3.055 billion base pair sequence of a human genome. Technological barriers have previously meant that 8% of the genome remained inaccessible. However, using sequencing technology from Oxford Nanopore, and others, this has finally been overcome.

Since its initial release in 2000, the human reference genome has covered only the euchromatic fraction of the genome, leaving important heterochromatic regions unidentified. The unknown sequence in the genome was primarily made up of highly-repetitive regions that have been impossible to resolve with traditional sequencing technology. Using nanopore technology, which can sequence DNA fragments at least as long as 4 million bases, and as such is the only sequencing technology able to span some of the largest and most complex regions of the human genome, the researchers have uncovered new information about the genetics of human health and disease.

Addressing the remaining 8% of the genome, the Telomere-to-Telomere (T2T) Consortium presents a complete 3.055 billion–base pair sequence of a human genome, T2T-CHM13, that includes gapless assemblies for all chromosomes except Y, corrects errors in the prior references, and introduces nearly 200 million base pairs of sequence containing 1956 gene predictions, 99 of which are predicted to be protein coding. The completed regions include all centromeric satellite arrays, recent segmental duplications, and the short arms of all five acrocentric chromosomes, unlocking these complex regions of the genome to variational and functional studies.

“In the future, when someone has their genome sequenced, we will be able to identify all of the variants in their DNA and use that information to better guide their healthcare. Truly finishing the human genome sequence was like putting on a new pair of glasses. Now that we can clearly see everything, we are one step closer to understanding what it all means”, said Evan Eichler, Ph.D., researcher at the University of Washington and T2T consortium co-chair.

In addition to spanning these complex regions, nanopore sequencing technology also provides real-time information about base modifications; this information about methylation of DNA is commonly being linked to disease, including cancer. Nanopore sequencing is the only approach to enable direct detection of methylation changes across the whole genome, and the sequencing of long fragments makes phasing of modifications simpler.

Reference: Nurk, S. et. al. 2022. The complete sequence of a human genome. Science. 376:6588, pp.44-53. DOI: 10.1126/science.abj6987
Original articles published by The Human Genome Project and Nanopore Tech on March, 31, 2022
Photo credit: Freepik