Almost a decade ago, I finished my PhD in archeology with a thesis that investigated the hunting and gathering behavior of early Homo sapiens and our extinct relatives, the Neanderthals.

To my non-archaeologist friends and family, I was the Stone Age expert, to whom all questions on any Paleolithic topic should be directed. I developed some strong opinions about the viral “ancestral” or “Paleo” diet. I did my part to contribute to the rebranding of Neanderthals as a type of human being and not a bunch of hairy, backwards brutes. To this day, my mom still emails me a link to any news article she finds about Neanderthals, Denisovans (another Paleolithic relative), or other ancient humans.

When I explain my research interests to new acquaintances, I am often asked questions like “what would you do if you met a Neanderthal?” or “do you think we will ever find a perfectly preserved frozen Neanderthal?” And, inevitably, “Could we clone a Neanderthal?”

At first glance, that last question seems fascinating. However, if we consider it more deeply, could we In fact Do you want to bring back a species of human that hasn’t existed on Earth for tens of thousands of years? What gives us the right to decide? Would it be ethical to do so?

What even is “de-extinction”?

In recent years, the idea of ​​“deextinction,” the reengineering or cloning of extinct species, has gained a lot of interest in the media.

Colossal Biosciences, a biotechnology and genetic engineering company, made headlines in 2024 claiming that they had achieved the first de-extinction of the direwolf. These are large, extinct canines (scientific name Aenocyon dirus) related to modern gray wolves (canine lupus).

Tens of thousands of years ago, dire wolves roamed grassland habitats in what is now North and South America. Visit the La Brea Tar Pits in Los Angeles and you can see an entire display wall lined with direwolf skulls excavated from their sticky graves, their bones stained a shiny nutty by tar.

Dire wolves became extinct about 10,000 years ago and around the same time as the mastodons, giant sloths and other megafauna that once lived in the Americas. Colossal’s initial “de-extinction” claims received a lot of backlash from the scientific community.

A summary of the project on the company’s website says: “[Colossal Biosciences] produced three living dire wolves: Romulus and Remus, born on October 1, 2024, and Khaleesi, born on January 30, 2025, marking the first successful de-extinction of a large predator in scientific history.” However, a few lines down the page, the summary reads:

“Colossal Biosciences brought back the dire wolves by making 20 targeted edits to 14 genes in the common gray wolf genome.”

The gray wolf genome contains about 19,000 genes. Colossal Biosciences edited 14 of those genes, a minuscule 0.073 percent change in the entire package of wolf DNA. Compared to a standard gray wolf, Colossal’s experimental pups are slightly larger and their coats are white instead of gray. However, direwolves are still a totally different species and genera of gray wolves.

In other words, these groups last shared a common ancestor about 5.7 million years ago, a relationship much more distant than the relationship between wolves and dogs. Put another way, wolves and direwolves are no more closely related than African wolves and jackals, or bison and gazelles.

The two species are so genetically different from each other that they probably could not have offspring together. Despite its bold claims, Colossal hasn’t done much more than create a gray wolf dressed in a dire wolf coat.

How does cloning work?

In 1996, a team of scientists at the University of Edinburgh took DNA from the nucleus of a sheep’s udder cell and implanted it into a different sheep’s egg.

Normally, an egg or sperm contains only half of an animal’s chromosomes, that is, half of its total genetic code. When the sperm fertilizes the egg, the two sets of semimicrosomes fuse, creating a new, unique combination. A cell from any other part of the animal’s body, called a somatic cell, contains the complete chromosome complement.

By exchanging the nucleus of a somatic cell for an egg, the research team created an embryo that would develop exactly as a fertilized egg normally would, but without any genetic contribution from a male parent. The resulting lamb, named Dolly, was an exact genetic copy of the sheep from which the original nucleus of the udder cells came.

After Dolly was born, cloning became a tremendously exciting field of study, and it wasn’t long before people were asking questions like “if we can clone an existing animal, can we clone an extinct species?”

Unfortunately, the answer is no, even with the leaps and bounds that genetic engineering has taken in recent decades. The problem is that cloning an extinct species requires a complete, intact DNA sample from that species, and that’s something we don’t have yet.

What would we really need to create a true clone of a Neanderthal?

The Human Genome Project, an international effort to map the individual genes on the 23 pairs of human chromosomes, formally began in 1990. The project officially ended in 2003, but the final complete map of the human genome was not completed until 2022, and the Y chromosome was completed in 2023.

Fragments of DNA from Neanderthal remains have also been reconstructed and stitched into a genome map over the past two decades. DNA is a surprisingly stable and robust molecule for something that appears so thin and fragile, but DNA that remains in soil for tens of thousands of years is still susceptible to damage from its environment.

Except any miracle Encino ManIn the style of the discoveries of frozen Neanderthal remains, a complete genome would have to be designed in a laboratory, not extracted from the bone.

Unraveling the Neanderthal genome is a great achievement, but knowing the location of all the genes is only part of the picture. It’s still not completely clear how many of those genes work with each other and how environmental factors might affect them.

To clone a Neanderthal by engineering the genome at a molecular level, scientists would need to recreate the same types of complex relationships that allow our genes to tell every cell in our body what to do.

There are major ethical concerns.

Us Homo sapiens We’ve been the only human species on Earth for tens of thousands of years, and as a population we’re pretty used to the idea. But go back about 60,000 years and there were several members of the genus Homo living in different parts of the world.

Neanderthals were a type of humans. We know this because traces of Neanderthal DNA still exist in our genome, meaning our respective populations interbred and mixed gene pools in the past. Therefore, the idea of ​​cloning a Neanderthal raises the same kinds of ethical concerns that accompany the prospect of cloning humans today.

Currently, the mortality rate of experimentally cloned animals is exceptionally high. Even when a cloned animal is successfully born, serious health problems often arise. Would we allow a human baby to suffer these stresses for the sake of scientific curiosity?

Human cloning also raises the question of what happens when we challenge individuality. Would a cloned human always see themselves as a shadow of their cell donor? We can’t know for sure. That’s why whenever someone asks me if I think we could clone a Neanderthal, I say no. For the moment, Paleolithic archaeologists will continue to raise and answer questions about the past by investigating the countless materials our early human relatives left behind.

In Ask us anythingPopular Science answers your most outlandish and mind-blowing questions, from the everyday things you’ve always wondered to the strange things you never thought to ask. Do you have something you’ve always wanted to know? ask us.

2025 PopSci Best of what’s new

The 50 most important innovations of the year