Scientists have completed the decoding of the remaining 8% of the human genome, providing a complete, gap-free genome sequence for the first time. This breakthrough, made possible by advanced sequencing technologies and the integrated efforts of more than 100 scientists globally, has unlocked the previously inaccessible section of repetitive DNA sequences that make up more than half of the human genome. The new DNA sequences reveal never-before-seen details about the region around the centromere, which plays a crucial role in genome organization, function, and chromosome segregation. This comprehensive reference map of the human genome provides invaluable insights into genetic variations and their role in evolution and human health.
In 2003, the Human Genome Project made history by sequencing 92% of the human genome, but the remaining 8% could not be fully sequenced due to the complexity of repetitive DNA sequences. Scientists have been working for nearly two decades to fill these gaps and sequence the genome in its entirety. This latest effort adds almost 400 million letters to pre-existing research, almost equal to an entire chromosome.
The newly completed genome, dubbed T2T-CHM13, represents a major upgrade from the current reference genome, called GRCh38, which is used by doctors when searching for mutations linked to disease and by scientists studying the evolution of human genetic variation. The sequences in and around the centromere total about 6.2% of the entire genome, or nearly 190 million base pairs, and provide a deeper understanding of the precise DNA sequences responsible for both health and disease, including cancer and birth defects.
The completion of the human genome sequence is a window into human evolution and the uniqueness of different species. It provides researchers with an invaluable resource to investigate repetitive regions that shape genetic structure and variation, species evolution, and human health. With more complete, “telomere-to-telomere” genome references, scientists can now explore a new era of genomics, untangling complex repetitive sequences across populations and species for the first time.
“This breakthrough is 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 bioinformatician Adam Phillippy of the US National Human Genome Research Institute.
The completion of the human genome sequence is a significant milestone in the study of genetics, providing a comprehensive reference map that will help researchers better understand the complexity and nuance of human biology and evolution.