(ORDO NEWS) — The Human Genome Project has been working for several decades, but only now scientists have managed to decipher all the sequences – from and to.
By 2003, in 10 years of work, scientists were able to decipher 92% of the genome, but it took them 20 years to complete the last 8. Biologists now have a complete picture of what genes make up our bodies
In 2003, the Human Genome Project presented a “complete” genome, but in fact it was 92% of the sequences other regions known as heterochromatic, located in the telomeres and centromeres of chromosomes at that time were considered too complex and expensive to sequence.
Now, after another two decades of work and technological advances, the entire human genome of about 3 billion bases has finally been sequenced without gaps.
This was done by a group of scientists called the Telomere-Telomere (T2T) Consortium. The new reference genome has been designated T2T-CHM13 and contains an additional 200 million base pairs of previously unknown DNA sequences.
Of these, there are 99 genes that appear to code for proteins, and about 2,000 candidate genes that will need to be studied more closely. The new version of the genome also corrects thousands of structural errors that were present in earlier versions.
What did the complete decoding of the human genome show?
Deciphering the last 8% took twice as long as the first 92%. This is because heterochromatic regions are made up of large chunks of repeating sections that are difficult to piece together.
If the genome is a jigsaw puzzle, then these sections are plain background pieces that can fit together in any number of ways.
To solve this problem, the T2T Consortium used several new tools to read longer sequences. After all, it’s much easier to complete a puzzle by working with a small number of large pieces rather than a huge number of tiny ones.
The researchers studied the genome using Oxford nanopore DNA sequencing, which can read up to a million bases in a single run with a small degree of accuracy.
Another method, known as PacBio HiFi, reads about 20,000 bases at a time with near perfect accuracy, so combining the two has proven to be an effective way to sequence the entire human genome.
Now scientists have a long analysis of the data obtained, which can lead to many breakthrough discoveries.
The members of the T2T Consortium plan in the future to create a reference pangenome of 350 human genomes to take into account the differences that can be observed from person to person.
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