Since its inception, CRISPR has allowedscientists make changes in the DNA in certain places of the genome. Often these point changes are made in turn. In any case, it was so before - but a group of scientists from Harvard University said that using this technique made 13,200 genetic changes in one cell. This is a record for gene editing technology.
How many changes can I make with CRISPR?
A group of scientists led by a gene technologistGeorge Church wants to rewrite the genomes on a much larger scale than has been possible up to now - which, she said, could ultimately lead to a “radical change” of the species, even a human one.
That is, scientists say in plain text that gene editing technologies will change the human species. For better or for worse? Do we recognize ourselves?
Edit genes on such a scale have already triedearlier. In 2017, an Australian group of scientists led by Paul Thomas “cut out” the Y chromosome in mice using gene editing and virtually destroyed it. Today, this strategy is seen as a potential treatment for Down syndrome, a genetic disorder caused by an extra chromosome.
To set a new record in the fieldgene editing, team members Oscar Kastanon and Corey Smith targeted CRISPR at a DNA sequence type called LINE-1, a mysterious recurring element that “litters” the human genome. These genetic elements, capable of replicating themselves, are estimated to constitute about 17% of our genome.
Because CRISPR cuts a double helix,making a large amount at one time simply kills the cell. In the past, this danger has limited attempts at large-scale editing. Jeff Faulkner of the University of Queensland in Australia says that in 2016 he tried to knock out LINE elements from 500 mouse embryos in the hope of seeing whether this would affect rodent behavior. But not a single mouse survived to leave offspring.
To avoid this problem, the Harvard teamadapted the CRISPR variant, called the basic editor, so that it does not cut the DNA, but replaces one genetic letter with another — say, turns C into T.
According to an article published in March on the BioRxiv preprint site, the team was able to make over 13,000 changes to some cells at once without destroying them.
"They found a way to conduct an experiment without causing significant instability in the entire genome," says Faulkner.
However, not all scientists agree thatlarge-scale editing of the genome will lead to such a radical change in our species. Gaetan Burdzhio of Australian National University called the idea "exaggerated."
Church himself sees in large-scaleediting the genome purification method by removing the genetic debris contained in it. In 2015, for example, in his laboratory they destroyed all 62 copies of the retrovirus, which is hidden in the genomes of pigs. Such viruses can be reactivated, so removing them from pigs will be an important step towards organ transplantation from pigs to humans.
According to Church, his ultimate goal isrepository of human organs or tissues with revised genomes that are immune to any viruses. He believes that this process - transcoding - will include about 9,811 point genetic modifications.
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