Romulus and Remus are genetically modified grey wolves
Colossal Biosciences
A company called Colossal Biosciences says it has revived an extinct species – the dire wolf. “On October 1, 2024, for the first time in human history, Colossal successfully restored a once-eradicated species through the science of de-extinction. After a 10,000+ year absence, our team is proud to return the dire wolf to its rightful place in the ecosystem.” That’s the claim made on the website of the US-based company. Here’s what we know.
What’s happened?
Colossal is claiming that three genetically modified grey wolf pups – two males called Remus and Romulus born in October, and a female called Khaleesi born in January – are in fact dire wolves. The same company also recently announced the creation of woolly mice and a nearly complete thylacine, or Tasmanian tiger, genome.
What is a dire wolf?
Dire wolves are large extinct canines (Aenocyon dirus) that lived in the Americas until around 10,000 years ago. The animals looked like large wolves with white coats. They were made famous by the Game of Thrones TV series – hence the name Khaleesi, after a main character in the program.
So, a dire wolf is an extinct species of wolf?
No. Grey wolves and dire wolves were thought to be very closely related based on their physical similarities but a 2021 study of ancient DNA revealed that they last shared a common ancestor around 6 million years ago. Jackals, African wild dogs and dholes are all more closely related to grey wolves (Canis lupus) than dire wolves are, despite their similar appearances.
Does that mean there are a lot of genetic differences between grey wolves and dire wolves?
Beth Shapiro of Colossal says her team has sequenced the complete genome of the dire wolf and will soon release it to the public. Shapiro could not tell New Scientist how many differences there are but said the two species share 99.5 per cent of their DNA. Since the grey wolf genome is around 2.4 billion base pairs long, that still leaves room for millions of base-pairs of differences.
And Colossal claims it has turned grey wolves into dire wolves by making just 20 gene edits?
That is the claim. In fact, five of those 20 changes are based on mutations known to produce light coats in grey wolves, Shapiro told New Scientist. Only 15 are based on the dire wolf genome directly and are intended to alter the animals’ size, musculature and ear shape. It will be a year or so before it’s clear if those changes have had the intended effects on the genetically modified animals, says Shapiro.
So these pups aren’t really dire wolves at all, then?
It all comes down to how you define species, says Shapiro. “Species concepts are human classification systems, and everybody can disagree and everyone can be right,” she says. “You can use the phylogenetic [evolutionary relationships] species concept to determine what you’re going to call a species, which is what you are implying… We are using the morphological species concept and saying, if they look like this animal, then they are the animal.”
What will happen to the gene-edited grey wolves that look a bit like dire wolves?
Shapiro says they are being raised on a 800-hectare reserve where they are being observed and cared for. “They can’t get a splinter without us knowing,” she says. There are no plans to allow them to breed.
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