The return of the dire wolf after 10,000 years of extinction

A "de-extinction" company says it has revived the long-eradicated dire wolf species using a new gene-editing technology.

The US start-up, Colossal Biosciences, said it had used "end-to-end de-extinction technology" to take DNA from a "13,000-year-old tooth and a 72,000-year-old skull" to create three "healthy dire wolf puppies".

While the company says it has "successfully restored a once-eradicated species", other scientists claim that the animals "are not truly dire wolves", given that much of their DNA is taken from grey wolves, and also that the "process raises ethical questions", said The Washington Post.

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What exactly is a dire wolf?

The dire wolf is a canine species that has been extinct for around 10,000 years, having lived up to 250,000 years ago. Living in the Americas, they are thought to have "died out as their prey did", said Scientific American.

They were "first described in the 1850s" after the discovery of their fossils, and are defined by their enormous size in comparison to modern wolves, growing "up to six feet in length" with white coats.

Recent studies have suggested dire wolves "share 99.5% of their DNA with grey wolves," despite previous findings describing the species as an "example of convergent evolution", in that they "separately evolve similar adaptations because they lead a similar lifestyle".

A 2021 study of ancient DNA samples suggested the two species "last shared a common ancestor around six million years ago" and that grey wolves are more closely related to "jackals, African wild dogs and dholes" than their ancient lookalike, said New Scientist.

How were the new wolves created?

Colossal extracted DNA from dire wolf fossils to create genomes, and then used them as a basis to modify the genes of grey wolves. The company says it used "20 precision edits" in the modifications, "15 of which were extinct gene variants not seen since the days of woolly mammoths over 12,000 years ago", to make them as close to dire wolves as possible, said New Atlas. Scientists were then able to create embryos that were carried by large domestic dogs.

The surrogate mothers gave birth to two male puppies, Remus and Romulus, in October and a female named Khaleesi (after the character in "Game of Thrones", a series which popularised dire wolves) two months later.

The main changes made to the genes were "intended to alter the animals' size, musculature and ear shape", but it will be "a year or so" before the animals have grown enough to clarify if the changes have worked, said New Scientist.

Are these really dire wolves?

While the chief science officer at Colossal, Beth Shapiro, said the company considered that "if they look like this animal, then they are the animal", other scientists are more sceptical of the claims of the revival of a long-extinct species.

Though Colossal's "technological feats are impressive", in reality, the company is "genetically engineering animals to look like extinct creatures", Nic Rawlence, an associate professor at University of Otago in New Zealand, told The Washington Post. He added that "we can't de-extinct extinct creatures" because "DNA is just not well enough preserved" to use cloning.

Other scientists "echoed" that sentiment, said TechCrunch, including Alexander Young, a professor of statistical genetics at UCLA, who said it was "massively overhyped" and though it was a "cool achievement", it is "not a dire wolf – it's a grey wolf modified to be more like a dire wolf".

What are the concerns?

Colossal is also planning the resurrection of the woolly mammoth and the dodo, among others. There are concerns that the re-creation of "the characteristics of extinct animals" gives "no incentive to conserve species and raises questions about where and how the animals will live", said Rawlence in The Washington Post.

As well as logistical questions, such as how scientists would "ensure a genetically diverse population", there were ethical questions over the mutated animals, including "who owns them", and whether "extinction companies trademark these creatures".

Colossal said it is already using the science to help preserve dwindling modern species, including the red wolf, of which it has already produced four puppies via surrogate mothers in the hope of eventually helping to boost the wild population.

There are no such plans with the dire wolves, which will be cared for by people on an 800-hectare reserve with no plans to let them breed.