Scientists are working to bring back a woolly mammoth-like species to roam the Earth’s tundra. A study published last year, however, complicates these efforts. Researchers at the Centre for Palaeogenetics in Stockholm found that woolly mammoths lost nearly 100 genes as they evolved.

Evolving Mammoth Genes

Love Dalén, professor in evolutionary genomics at Stockholm University, explained that such alterations to genes can change pathways, which affect key traits.

“From an evolutionary perspective, what this means is that since these deletions have become fixed in the wooly mammoth, that means that they are somehow adaptive,” says Dalén.

But this is still a hypothesis, and the findings raise further questions. “We don’t know when these deletions evolved,” Dalén says. “It could have been any time since woolly mammoths diverged from the elephant, about five million years ago.”

What Genes Changed?

In total, 84 genes were deleted and three were short insertions, altering the genome structure. Researchers suggest it’s likely these modifications were necessary for mammoths to adapt to the cold, northern environments in which they lived.

“Several of the genes that have been affected are related to classic woolly mammoth traits such as fur growth and hair shape, fat deposition, as well as skeletal morphology and ear shape,” Marianne Dehasque, a student at the Centre for Palaeogenetics, says in a statement.

Researchers analyzed multiple woolly mammoth genomes and compared them to previously sequenced mammoth and elephant genomes. Their results suggest modifications over time led to the “unique phenotypic adaptations of the woolly mammoth, and were potentially critical to surviving in its natural environment,” the researchers write.

Looking at the Whole Mammoth Genome

To confirm these deletions are linked to adaptation, the research group now aims to sequence genomes from across the mammoth’s evolutionary lifespan to better understand when these traits evolved.

“What we will be doing going forward is to create a genomic transect over the last million years to understand when these changes happened,” Dalén says. “Are they evolving in concert, or are they evolving more rapidly during certain periods, for example of climate change? So, that is our ultimate goal.”

More recent work – which sequenced the genomes of 23 woolly mammoths – discovered that their common fluffy traits developed and intensified over time from their initial split with elephants.

When Did the Woolly Mammoth Go Extinct?

This lumbering and notoriously shaggy-haired relative of elephants roamed the earth for around five million years before disappearing around 4,000 years ago. Humans played a part in that demise, but research suggests it was a changing climate that led to the extinction.

Dalén and his team began their work studying the last remaining population on Wrangel Island. Their research also led to the sequencing of mammoth DNA dating back over one million years, a “groundbreaking” find, according to Dalén, as it showed it is possible to peel pack genetic layers this far in time.

Bringing Back the Woolly Mammoth

The DNA findings also impact an ongoing de-extinction project run by Colossal Laboratories. Scientists are working to bring back a mammoth-like cold-adapted elephant, as well as other extinct species such as the dodo, using CRISPR technology.

“My view is it’s going to be very difficult to do this project, but on the other hand, it’s an interesting endeavor,” Dalén says. “In the mammoth’s case, you will need to remove parts of the elephant genome.”

Not doing so “could potentially preclude reintroduction and survival of a resurrected woolly mammoth in its natural habitat,” according to the study. It’s not beyond the realms of possibility and, relatively speaking, with CRISPR technology it can be done, Dalén adds, “It’s just another thing you have to do.”

The research group’s findings may have a global impact if the mammoth is to return, but Dalén explains their core reason for pursuing such questions is focused on the basic science.

“We are interested out of curiosity to know what makes a mammoth into a mammoth; where they come from and how evolution happens,” he says.

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