June 25, 2022

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Discover limitations that make it useless to revive extinct species

Discover limitations that make it useless to revive extinct species

Researchers from the University of Copenhagen and Shantou have just shown that the idea of ​​reviving extinct species by genetic engineering is more complex and challenging than previously thought. The revival of extinct species such as the dinosaurs 67 million years ago, or the mammoth 4,000 years ago, is in the collective imagination in general and in paleontology in particular. spoilers: It cannot be done.

The Brown Rat on Christmas Island

Posted in cell reports I ran into a problem: DNA also evolves. They change places, genes interact with each other differently in some species and in others, and it’s impossible to see these differences just by comparing sequences. They came to this conclusion in an attempt to complete the genome of the extinct brown rat Ratus Mairis Christmas Island.

They chose this species because it became extinct in the early 20th century and was related to a distant, well-studied cousin. There were two samples in the Oxford University collection, so the DNA could easily be recovered. A distant cousin to which the extinct species can be compared, the Norwegian brown rat, is a species with a long history of research, for which full genome information has been available.

Extinct species may have unknown genome DNA

Researchers were able to sequence 95% of the genome of Ratus MairisBut the remaining 5% didn’t match or match anything to compare. “Some genes have evolved so much in species related to the species we are trying to recover that it is impossible to reproduce them, not because there is no DNA, but because it is unrecognizable,” Gilbert comments in remarks to vanguard.

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“DNA has been fragmented into short pieces, and because some genes in the extinct form have evolved to look very different from the living form, there are parts of the genome that we cannot recover,” Gilbert explains.

“The theme of evolution is like taking a page out of a book in Spanish and comparing it to the same page in Spanish. Easy. Now compare it to Portuguese. Some of the words make sense, others get more difficult because some of the words are spaced out further” Now move to Latin. The further apart the words, the more difficult it is to recognize them. And in a genetic context, if you can’t identify it, you can’t make the alterations in the brown rat, which is our case. “

Mammoths can, dinosaurs can’t

This problem affects 5% of the genome in this case. The feasibility of interpreting missing DNA is an issue that must be evaluated in advance, thanks to this research, when dealing with gene editing and reconstructing the genomes of extinct species. The first limit is the limit for available DNA. “DNA lives in cold conditions for a few hundred thousand years at most,” Gilbert explains. “Normally,” he says, “some exceptions are up to a million years old, which makes it completely pointless to recover dinosaur species, since they don’t have DNA in them, but in mammoths it can happen, because there’s DNA left.”

For the species being investigated in gene editing for the possibility of one day reproducing them, the researcher explains, “The only current efforts are mammoths, marsupials and homing pigeons.” He insists that “there are attempts to cross animals to recover the cuaga and capercailie, but it must be borne in mind that they are only concerned with appearance, not the genetic base.”

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But appearance is not everything. Regarding Ratus Mairis, the genes that the researchers were unable to specifically reproduce were those related to smell and the immune system, both vital abilities for survival. In future research, Gilbert and his team will test gene modification on a non-extinct species, that is, turning a black rat into a Norwegian brown rat. As Gilbert mentioned cell, although he’s scientifically excited about the idea, the process makes him wonder “I think it’s a great idea in technology, but one has to ask if it’s the best use of money rather than keeping things alive.” is the reasons.