New geniuses, 3,400 more than we knew so far: the book of life has finally been completed and its pages that were still blank, equal to about 8% of the volume, have been written. After 20 years, the map of the human genome has been completed thanks to an unprecedented technological effort and the result is online on the BioRxiv website, which welcomes articles awaiting examination by the scientific community.
The numerous authors of the research, who belong to the T2T consortium (Telomere-to-Telomere), thus opening the way to the possibility of knowing the single chromosomes at a level of detail never reached before, with repercussions in many fields of biomedicine, from diagnosis to innovative therapies. At the moment, however, the most interesting element it concerns the technologies that have made it possible to achieve this and that have been shown to work efficiently.
The first author of the research is Sergey Nurk, computational genomics expert of the American National Institutes of Health (NIH) and the University of California in Santa Cruz, those of Washington in Seattle and the National Human Genome Research Institute in Maryland are represented.
The new map of human DNA it now includes 3.9 billion base pairs, compared to 3.2 in the first sequence obtained 20 years ago by the International Consortium for the Sequencing of the Human Genome and, in parallel, by the small Celera company headed by Craig Venter. Unlike the map obtained 20 years ago, the one just made known was not obtained from the DNA of an individual, but from the result of an abnormal pregnancy, that is, from the growth in the uterus of an oocyte without a nucleus (a so-called ‘molar pregnancy’ or ‘hydatiform mole’), which thus contained two copies of the same 23 chromosomes, instead of two different sets of chromosomes, like normal human cells.
A allow you to complete the map were the new DNA sequencing technologies developed in recent years. Thanks to these it was It is possible to fill the gaps and gaps left 20 years ago and that corresponded to about 8% of the genome. “This study represents an important step forward from a technical point of view because it proves, if confirmed, that it is now possible to sequence the chromosomes in their entirety, from one extreme to the other,” observes the director of the Human Technopole, Iain Mattaj. The technology available at the time of the first map “did not allow sequencing those stretches of DNA that repeat very frequently and make up about 5% of the human genome.
The new data – continues Mattaj – were obtained from uncommon human cells, which have two identical sets of the same 23 chromosomes, but it is a proof of principle that it will now really be possible to obtain complete sequences of the genome. In addition to highly repeated DNA sequencing, which is thought to be involved both in the regulation of gene expression and in the evolution of the genome, the research – says Mattaj – reveals 3,400 new protein-coding genes, 4% more than those identified in the draft of the genome “.
For the T2T consortium researchers, their result represents “the greatest advancement in knowledge of the human genome since the publication of the first map”. The number of bases, i.e. of the words in which the book of the human genome is written, is 4.5% increase and the genes that control the production of proteins are now 0.4% more: for the authors of the research these new insights may still be sufficient to understand still unknown aspects of the human genome, for example the way in which genes are regulated.