• The startup looking to bring back the woolly mammoth announced a breakthrough in its work. 
  • Colossal Biosciences says it created elephant cells that can be reprogrammed to make other cells.
  • The project is being led by George Church, a Harvard genetics professor.

The startup that wants to bring the woolly mammoth back from the dead said it is inching closer to its goal after a breakthrough in creating reprogrammed elephant stem cells.

The advance is "momentous" as it could unlock several fields of research, including how to make the building blocks for a mammoth baby, Ben Lamm, cofounder and CEO of Colossal Biosciences, said in a statement.

Its hope is to bolster biodiversity by bringing back lost species while also helping species on the brink of extinction survive harsh changes like the climate crisis.

The company, which Business Insider was told is currently valued at $1.5 billion, has grand plans. These include bringing back the woolly mammoth and the dodo.

"Each step brings us closer to our long-term goals of bringing back this iconic species," said Lamm. Colossal Biosciences thinks it can create a mammoth-like, gene-edited creature through IVF by 2028.

It could also help living elephants, which are notoriously tricky to study in the lab, the firm said.

"Elephants might get the 'hardest to reprogram' prize, but learning how to do it anyway will help many other studies, especially on endangered species," said Colossal cofounder and Harvard geneticist George Church.

Stem cells occur naturally in the body. They are special because they can evolve into pretty much any cell type — bones, hair, skin, organs — provided they are told what to do.

To program them, the body bathes the cells in a complex mix of chemicals that nudge them toward their final cell type. This is called differentiation.

This process was long thought not to be reversible, but in the early 2000s, scientists figured out a cocktail that could turn differentiated cells back into stem cells.

This was a boon for biologists, who could then reprogram these stem cells, called iPSCs, into cell types they didn't necessarily have access to before in the lab.

This dedifferentiation cocktail worked on most species, including humans, monkeys, big cats, and birds. But elephant stem cells remained remarkably resistant to the process, per the statement.

After tweaking the chemical composition of the mixture, Colossal Scientists say they've finally cracked it.

"We knew when we set out on the woolly mammoth de-extinction project that it would be challenging, but we've always had the best team on the planet focused on the task at hand," said Lamm.

This offers avenues to understand better how to make a mammoth. It means the scientists can create cells like hair and cold-busting fat storage in the lab.

"We are most excited to use the cells we have developed to grow elephant gametes in a dish," said team lead Evan Appleton in the statement.

Gametes are the sperm and egg cells that fertilize to make an embryo. If the scientists could make them in the lab, they could create them without having to resort to harvesting them from elephants.

"The goal, I think, is to turn these iPSCs into sperm and eggs, which would allow for in vitro fertilization and, eventually, surrogacy," Vincent Lynch, a developmental biologist and associate professor at the University at Buffalo in New York who was not involved in Colossal's work, told Live Science in an email.

"Those methods are pretty challenging and haven't been developed yet, but it is only a matter of time," said Lynch

The research could also help scientists better understand how elephants carry their babies.

"Elephant gestation is so long and complex, so really understanding the developmental biology aspect of elephant biology is so important," Eriona Hysolli, the head of biological sciences and mammoth lead at Colossal Biosciences, told Live Science.

This doesn't mean the team will be rolling out baby mammoths tomorrow, though, Hysoli told Live Science.

Understanding how to turn tweak these elephant stem cells into cells from the extinct species will be another hurdle to tackle going forward.