Jurassic mammoths?

Shaggy-coated and large-tusked, woolly mammoths once roamed the cold tundra of Europe, Asia, and North America. Mammoths became extinct thousands of years ago, but now Colossal, a biosciences and genetics company, wants to bring these pachyderms back to life. Using cutting-edge genetic engineering technology, Colossal aims to insert mammoth DNA into Asian elephants to create a “cold-tolerant elephant mammoth hybrid.”

Co-founded by geneticist George Church and tech entrepreneur Ben Lamm, the Dallas-based company Colossal is targeting 2027 for its first round of woolly mammoth calves. The company’s founders believe rewilding the Arctic region’s over-shrubbed forests with elephant-mammoth hybrids will revitalize the mammoth steppe (grasslands largely devoid of trees), a development they claim could reduce greenhouse gas emissions and mitigate climate change. Colossal has so far raised at least $225 million in investor funding.

The prospect of bringing back extinct animals sounds like science fiction out of Jurassic Park, but some experts believe it is possible. Outside scientists have variously expressed either excitement or dismay about the idea, and some suggest Colossal’s claims about combating climate change are overstated.

Thanks to layers of permafrost in northern climates, scientists have been able to extract woolly mammoth DNA from frozen mammoth carcasses. Woolly mammoths and their closest living relatives, Asian elephants, share 99.6 percent of their DNA, according to Colossal. Key mammoth genes include those responsible for mammoth hair and insulating fat layers.

Using gene editing technology, Colossal scientists are copying mammoth genes into the skin cells of Asian elephants to form hybrid elephant-mammoth stem cells. Ultimately, Colossal wants to grow these hybrid stem cells into embryos that will be gestated by a surrogate African elephant.

The company faces several technical challenges. Co-founder George Church said in an email those include the need for extensive computer-assisted analysis of genomes from both mammoths and ­elephants, gene editing of multiple DNA sequences simultaneously, and pulling off somatic cell nuclear transfer, in which an embryo is created from a body cell and an egg cell.

Joseph Frederickson, a vertebrate paleontologist who directs the Weis Earth Science Museum at the University of Wisconsin Oshkosh and is not involved in Colossal’s research, said none of the individual technologies the company uses are new. But Colossal is breaking new ground by combining these technologies to stitch together DNA from creatures separated by thousands of years. Despite the genetic similarity between Asian elephants and woolly mammoths, Frederickson estimates Colossal will need to tweak thousands of genes to achieve its goal. While that’s a tall order, he thinks it’s possible.

A skeleton of Mammuthus, the mammoth, is on display at the American Museum of Natural History in New York. Mary Altaffer/AP

Others are less optimistic. Stuart Pimm, professor of conservation ­ecology at Duke University, doubts Colossal will succeed in de-extincting animals. And if it did, he doubts the animals would survive in the wild, since the Arctic’s ecosystem is vastly different today than it was when mammoths inhabited it.

Calvin Beisner, president of the Cornwall Alliance for the Stewardship of Creation, hopes Colossal will ­succeed in its mammoth restoration effort. From a Christian perspective, Beisner sees no problem with de-­extincting animals. “I think it would be a wonderful exercise in the dominion that God has instructed mankind to exercise in His world,” he said.

But Beisner doubts that bringing back woolly mammoths will significantly lessen climate change. He suggested that rather than converting the Arctic region to grasslands, re-foresting it would be more effective in countering global warming. That’s because trees sequester vast amounts of carbon dioxide.

Frederickson agreed that Colossal’s climate change claims are misplaced, noting any benefit would be minimal compared with human sources of CO₂ emissions.

Church disputes that characterization. He argued the modern Arctic region is already thick with trees and said grasslands better protect the ­carbon-rich permafrost layer from melting, thereby preventing carbon emissions. He also said hybrid elephant-­mammoths are more likely to survive than modern endangered ­elephants, living farther from human conflict and possessing both more range and more genetic diversity.

Other labs are attempting work similar to Colossal’s. Wildlife conservation organization Revive & Restore, for instance, has been working on restoring the extinct passenger pigeon since 2012.

Colossal also hopes to de-extinct the dodo, a flightless bird that lived on the island of Mauritius a little over 300 years ago, and the Tasmanian wolf, which died off only last century. Both species were exterminated by human intervention. The question now is, can human intervention bring them back?