The first draft of human genome sequence was produced after two decades of Human Genome Project. Recently, researchers from National Human Genome Research Institute, National Institutes of Health, University of Washington, Santa Cruz, and University of California have worked in collaboration and completed 32 years old quest by uncovering the first complete, gapless DNA sequences that make up a human genome. According to the researchers, having a gapless sequence of around 3 billion bases in our DNA is very important to better understand the genomic variation and genetic contribution in different diseases.

Generating a complete genome sequence is an incredible scientific achievement, as this foundational information will more strengthen the ongoing efforts to understand all nuances of human genome, and ultimately will empower the genetic level studies on human diseases. The full genome sequencing builds under Human Genome Project which have mapped around 92% of the genome since research undertaken. Later on, thousands of scientists developed the computational methods, laboratory tools and different approaches to uncover the complex sequence. The remaining 8% of the sequence includes many repetitive DNA and comparable to entire chromosome in size.

Over the past decade, new technologies on DNA sequencing have emerged that can produce a longer sequence read. Oxford Nanopore sequencing technique can produce an accurate single reading of 1 million DNA bases. While the PacBio HiFi method can read up to 20,000 bases with perfect accuracy. Researchers in telomeres 2 telomeres (T2T) consortium have used both above mentioned sequencing methods and made breakthrough in understanding the most difficult and repeating part of human genome by using long-read methods. Beside this, the complete genome sequence was generated by using special cell line in which each chromosome has two identical copies, unlike the most of human cells which carry two different copies.

Co-chair of the consortium, Dr. Adam Phillippy said that “sequencing the entire genome will be more straightforward and less expensive in coming years”. Phillippy further added that “when someone has its complete genome sequence, then it will be easy for researchers to identify all the variants in DNA and this information will be better to understand the healthcare. Generating the complete human genome sequencing is like putting a new pair of glasses, and we can see the everything clearly.”

Importantly, these researchers inspired a revolution in fight against the human diseases and provided a new way to future of medicine, although that future is still need to be fully realized.

Reference:

• Sergey, N., Koren, S., Rhie, A., Rautiainen, M., et al. The complete sequence of a human genome. Science, 2022; 376 (6588): 44 DOI: 10.1126/science.abj6987