[REVIEW] : The human genome fully decoded, after 30 years of research

Is a milestone in the history of biology about to replace another? In February 2001, an international scientific consortium published, after twelve years of effort, the first sequence of a human genome. Nothing less than the “making” secrets of a typical Sapiens. However, the mission is only partly completed: the published sequence has holes that the experts fill with “false text”.

The human genome is now complete

A complete, gap-free sequence of the human genome has been published by the Telomere to Telomere (T2T) consortium associated with the American Institute for Human Genome Research.

This breakthrough is the subject of six articles published in the magazine Science(New window) and a handful of others, published in specialized journals.

The announcement comes nearly 20 years after the announcement of the completion of the first draft of the human genome on April 14, 2003.

At the time, the Human Genome Project was the culmination of a decade of work involving dozens of scientists from six countries and with a budget of around $3 billion. It had made it possible to map approximately 92% of the genome.

Landmarks

  • It can be compared to a 23-chapter instruction book formulating the distinctive features of a person and allowing the proper functioning of his body.
  • Genetic material is present in every cell of a person. Thus, the nucleus of each human cell contains between 20,000 and 25,000 sentences (genes) and more than 6 billion letters (these are the letters A, C, G, and T).
  • Each cell reads the genes that concern it. For example, a skin cell reads information about skin texture and amount of hair, but does not read instructions about the eyes or the heart.

The remaining 8%

The sequencing announced Thursday is equivalent to the 8% that remained to be mapped. It comes to complete the work announced in 2003, but also all the research efforts carried out in the last two decades and which have benefited from new decryption techniques making the sequencing work much less laborious and much more precise.

This percentage mainly corresponds to “holes” in the sequences related to the fact that the technology of the time was unable to complete the puzzle in more difficult places of the chromosomes which include areas.

Thanks to new technologies, researchers have been able to realize the genome close to the centromere, the middle of the chromosome, and in the telomeres that are at the end of the chromosome.notes Stephanie Lord-Fontaine.

All of these technological breakthroughs have also improved sequencing on a much more practical level. $ and can take a few days”,”text”:”Sequencing a complete human genome today costs $1000 and can take a few days”}}” style=”border: 0px; font-style: normal; font-variant: inherit; font-weight: inherit; font-stretch: inherit; line-height: inherit; font-family: inherit; font-size: 17px; margin: 0px; padding: 0px; vertical-align: baseline; quotes: “« ” ” »”; box-sizing: border-box;”>Sequencing a complete human genome today costs $1,000 and can take a few daysshe explains.

“We thought there was no relevant information in those areas, but they are actually linked to about 600 genes that would be medically relevant. »

— A quote from Stéphanie Lord-Fontaine

One of the researchers who participated in the work revives the literary comparison. In the great manuscript of life we ​​have access to chapters that have never been read beforesaid Evan Eichler, a physician at the University of California at Santa Cruz.

The complete map of the human genome finally unveiled

Two decades after a first version, “holes” and errors have been corrected thanks to major advances in sequencing.

It is now possible to affirm that the complete genome comprises 3.1 billion base pairs which constitute a sequence of four letters, A, T, C or G, carried on two strands in the form of a double helix. Scientists sequenced an additional 225 million base pairs that had not been identified or located. These new regions suggest that 182 proteins present in the human species had not yet been identified.