Genome without omissions
Scientists have completely sequenced the human genome, ushering in a new era in genomics
Svetlana Maslova, Hi-tech+
The work of an international team of researchers is called a breakthrough in genomics, as for the first time scientists have gained a complete understanding of the sequence of all base pairs. Until now, information about 8% of the genome was missing due to technological limitations. They were overcome thanks to a new sequencing technology that does not cut DNA into small pieces (because of this, losses occurred), but scans it entirely with a special laser.
In 2003, scientists from the Human Genome project announced the first genome sequencing, which produced an absolute revolution in genomics. The discovery was preceded by thirteen years of research, but then the genome was not 100% read. Now an international team of authors has stated that they have received information about the missing 8%. Their work (Nurk et al., The complete sequence of a human genome) is currently available as a preprint and is awaiting peer review.
"We have completed the creation of the first complete sequence of 3.055 billion base pairs of the human genome and these are the largest reference changes since its initial discovery," the authors said.
The genome is the sum of all DNA and mitochondrial DNA (mtDNA) sequences in a cell. It contains all the instructions necessary for survival and reproduction, which consist of so-called building blocks or base pairs G, A, T and C. Their order encodes biological information.
In humans and other mammals, copies of almost all DNA are present. For example, we have pairs of chromosomes, one from each parent, but for researchers, the value is the sum of only one copy of the base pairs. In fact, the size of the human genome is approximately 6 billion base pairs, but scientists use only half as a "representative" copy.
According to the authors, 8% of the genome was missed in 2003 not because of the lack of important information in them, but because of technological limitations. Now scientists have managed to overcome them thanks to a new sequencing technology developed at California Pacific Biosciences and the British Oxford Nanopore. Its difference is that DNA is not cut into small pieces due to the risks of errors, but is read in a special way by a laser.
Currently, the work is awaiting expert evaluation and approval. If all the results are confirmed, the discovery will mark a new era in genomics, when none of the areas of the genome will remain hidden from researchers.
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