Should Scientists Clone Extinct Species?

What could be more thrilling than cloning dinosaurs? And then letting them roam free on an island! Well, Jurassic Park showed us how this could have terrifying results.

Did you know?

The gastric brooding frog went extinct in the early 1980s. The scientists behind the Lazarus Project tried to bring it back. TIME magazine named the project one of the 25 Best Inventions of 2013.

That movie was released more than 25 years ago. Now, scientists have figured out how to bring extinct species back to life. 

Species that have gone extinct within the last few thousand years could be candidates for de-extinction. The process is also called resurrection biology or species revivalism. And all it requires is some preserved cells or traces of DNA.

But is it really a good idea to have great auks, sabretooth cats and woolly mammoths roaming the Earth again?

How do you clone an animal?

Somatic cell nuclear transfer (SCNT) is one way of cloning an animal. It requires intact cells from an extinct species. First, scientists remove the nucleus from an egg cell of a closely related still-living species. Then they replace it with the nucleus from the cell of the extinct species. 

For example, they could replace the nucleus of an elephant’s egg cell with the nucleus from the cell of a woolly mammoth. This replaces the elephant’s genetic code with that of the woolly mammoth. 

An electrical pulse causes the cell to start multiplying. If all goes well, an embryo will develop. The embryo is then placed in a female animal from the species that provided the egg.

Did you know?

SCNT was used to create Dolly the sheep, the first cloned mammal.  

However, it can be very hard to find intact cells from extinct species. Usually, scientists can only find pieces of DNA. These partial DNA samples may have been preserved in permafrost or in museum specimens. Pieces of DNA can be used to help reconstruct the genome (genetic blueprint) of an extinct species. 

First, genes responsible for extinct traits are synthesized in a lab. They can then be gradually spliced (inserted) into the genome of a closely related living animal. This process is called genetic engineering.

How have cloning efforts gone so far?

The first attempt at de-extinction was made in 2009. Scientists used preserved cells to clone a Pyrenean ibex. This species of wild goat went extinct in January 2000. 

The attempt was successful. However, the clone had a defective lung. It died just seven minutes after it was born. Dolly the sheep suffered a similar fate. She died at the age of six, after tumours were found in her lungs. In fact, most clones are unhealthy and live short lives.

Why do clones often die young? It’s because DNA taken from adult cells has been damaged by aging. Every time a cell divides, there are mutations and small losses of DNA. Over time, this damage builds up. Scientists also damage DNA during the cloning process. This happens no matter how carefully they handle the DNA.  

Did you know?

Scientists could avoid problems related to DNA damage by using stem cells. In fact, stem cells could revolutionize cloning.

Is de-extinction a good idea?

De-extinction supporters say we have a moral obligation to bring back some extinct animals. They point out that humans are directly responsible for the extinction of many species. For example, the passenger pigeon, Steller’s sea cow and the dodo all disappeared because of hunting, habitat destruction and disease. 

Supporters also see de-extinction as a way of increasing biodiversity. This could benefit ecosystems. For example, large grazing herbivores like woolly mammoths could improve soil quality. They could turn barren tracts of Siberian tundra back into rich grassland. 

Finally, research on de-extinction could lead to ways of saving endangered species.

De-extinction opponents argue that it could take resources away from conservation efforts. This would put even more species at risk of extinction. 

Also, reintroduced species could have a hard time surviving in the wild. Many of their old habitats are gone. They would lack defence mechanisms to protect themselves from unfamiliar predators. And their immune systems might not be equipped to deal with new pathogens. Once infected, they could spread diseases to other species. 

It’s not at all clear who will win the debate. And we don’t know exactly where research on de-extinction will lead. Clearly, difficult decisions will need to be made. What would you do?