The findings were published Thursday in six articles in the journal Science. According to the researchers, the existence of a complete, non-empty sequence of about 3 billion letters in human DNA is crucial for understanding the full spectrum of the human genomic variant and for understanding the genetic contribution to certain diseases. The project was carried out by the research team from the Telomere to Telomere (T2T) consortium, an open, community-based effort to create the first complete human genome assembly. The team was led by researchers from the US National Human Genome Research Institute (NHGRI), the University of California at Santa Cruz and the University of Washington in Seattle. “Having this complete information will allow us to better understand how we form as an individual organism and how we differ not only from other humans but also from other species,” said Evan Eichler, lead researcher and professor of genomics at the University of Washington. In 2003, the Human Genome Program made history when it analyzed the sequence of 92 percent of the human genome. But scientists have been struggling to decipher the remaining 8 percent of the human genome for nearly two decades because of its complexity. That last 8 percent contains many genes and repeat DNA and is comparable in size to an entire chromosome, the NHGRI said. The new research used a human cell line with only one copy of a chromosome for sequencing, instead of using typical human cells, which carry two copies of each chromosome, one maternal and one paternal copy. The researchers noticed that most of the recently added DNA sequences were close to the repeating telomeres. The full sequence of the human genome will now be particularly valuable for studies that aim to create comprehensive views of the human genomic variant or how human DNA differs, according to the NHGRI. “Creating a truly complete human genome sequence represents an incredible scientific breakthrough, providing the first complete view of our DNA profile,” said Eric Green, NHGRI Director. “This fundamental information will reinforce the many ongoing efforts to understand all the functional nuances of the human genome, which in turn will enhance genetic studies of human disease,” Green said. According to T2T consortium co-chair Adam Phillippy, whose NHGRI research team led the final effort, sequencing an entire individual genome will become less costly and simpler in the coming years. “In the future, when someone submits the sequence of their genome, we will be able to identify all the variants in their DNA and use this information to better guide their healthcare,” Phillippy said. “Really completing the sequence of the human genome was like wearing a new pair of glasses. Now that we can see everything clearly, we are one step closer to understanding what everything means,” he said. Enditem
