Scientists Grow Elephant Stem Cells in Key Step Toward Woolly Mammoth ‘De-Extinction’

The team’s lofty goal of “resurrection” is still far from reality, but scientists say the advancement in understanding cells could help with elephant conservation

A black-and-white drawing of two woolly mammoths walking through snow
Some researchers say that "bringing back" woolly mammoths could help protect frozen tundras by slowing the melting of permafrost. Bettmann / Contributor via Getty Images

Scientists from a company attempting to “resurrect” the woolly mammoth have achieved a key breakthrough in their work—for the first time, they have turned Asian elephant cells into stem cells, which can develop into any type of tissue.

The cells could play a role in efforts to conserve threatened species and bring others back from extinction, the researchers write in a paper posted to the preprint server bioRxiv on Wednesday. The research has not yet been peer reviewed.

The company, Colossal Biosciences, says it is trying to “de-extinct” the woolly mammoth—and by that, it means its scientists aim to genetically engineer a cold-resistant elephant with the biological traits of the mammoth. Their goal, in part, is to preserve the arctic ecosystems the giants once roamed.

“These cells definitely are a great benefit to our de-extinction work,” Eriona Hysolli, a co-author of the study and the head of biological sciences at Colossal, tells Live Science’s Sascha Pare.

“It’s probably the most significant thing so far in the project,” study co-author George Church, Colossal’s co-founder and a Harvard University geneticist, tells the Washington Post’s Dino Grandoni. “There are many steps in the future.”

Ultimately, the researchers want to edit elephant DNA to incorporate traits that allowed mammoths to survive the cold, like shaggy hair, curved tusks and fat deposits. Then, they plan to fuse an edited stem cell to an Asian elephant egg and implant the egg in a surrogate, breeding a mammoth-like elephant.

But the researchers only had a limited supply of elephant cells on which to study gene editing, so they tried to make their own cells, writes the New York Times’ Carl Zimmer. Only 30,000 to 50,000 Asian elephants remain in the wild, providing only limited access to existing cells to use, according to Wired’s Matt Reynolds.

Induced pluripotent stem cells, or iPSCs, can theoretically be converted into any other type of cell, including the embryonic cells needed for de-extinction efforts, according to the study. Researchers first derived iPSCs from mouse cells, and they have since been derived for humans, cows, pigs, goats, rhinoceroses and other animals.

But the development of elephant iPSCs has proven to be more challenging. Many teams of researchers have tried and failed in the task. But the Colossal team made a breakthrough when they blocked the expression of an anti-cancer gene elephants have, writes Nature News’ Ewen Callaway. Elephants rarely get cancer, which is unexpected for a large animal with so many cells, and the elephant stem cells could shed light on why this is the case, the study authors write.

The elephant iPSCs the researchers made “seem to pass all the tests with flying colors,” Church tells the New York Times.

“There is more validation to be done, so until you do the experiment you can never be sure, but we think that the pluripotency potential [to differentiate into any cell type] is fully there,” Hysolli tells Live Science.

However, “there are still steps before we can call them proper iPS cells,” Sebastian Diecke, a stem-cell biologist at the Max Delbrück Center in Germany who did not contribute to the findings, tells Nature News.

Despite this advance, scientists still have a long road ahead before any mammoth-like elephants are born.

Matthew Cobb, a zoologist at the University of Manchester in England who was not involved in the research, tells the Washington Post that the researchers may be unable to introduce the mammoth gene edits to the elephant cells or get the embryos to develop.

“I have no doubt that given enough time and money they will overcome the technical challenges of making a woolly-mammoth-looking elephant,” Vincent Lynch, a developmental biologist at the University of Buffalo who did not contribute to the findings, tells Wired.

But the creatures that researchers want to resurrect are more than just strands of DNA—they also have specific behaviors that will likely have to be learned. “They’ve got no elders to raise them, to teach them,” Heather Browning, a philosopher studying animal welfare at the University of Southampton in England who was not involved in the research, tells the Washington Post. The animals would have “no way of learning how to be mammoths.”

“We know almost nothing about the genetics of complex behavior,” Lynch tells the New York Times. “So, do we end up with a hairy Asian elephant that doesn’t know how to survive in the Arctic?”

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