The idea of bringing extinct animals back to life continues to fascinate the realms of science fiction. A group of scientists from Harvard University seem to have taken us one step closer to that goal. In what seems to be an inspiration from ‘Jurassic park’, they have successfully managed to copy genes from frozen woolly mammoths and paste them into the genome of an Asian elephant.
Woolly mammoths (Mammuthus primignius) may have appeared during the middle Pleistocene more than 400,000 years ago, but they actually died out around 4000 years ago somewhere near the Wrangel Island in the Arctic Ocean. Since these animals resided in frozen parts of the world, their dead bodies have been remarkably well preserved. It was these carcasses which provided the DNA used by the scientist at Harvard.
Mammoths are closely related to Asian elephants, so that the Harvard scientists didn’t need to fully create a new cell. Using a DNA editing tool called CRISPR, the scientists spliced genes for the mammoths’ small ears, subcutaneous fat, and hair length and color into the DNA of elephant skin cells. The tissue cultures represent the first time woolly mammoth genes have been functional since the species went extinct around 4,000 years ago.
“We have not published it in a scientific journal because there is more work to do, but we plan to do so.” lead researcher George Church told the Sunday Times.
This work is part of an effort to recreate extinct species, a process called “de-extinction”. The recent breakthrough shows that one proposed de-extinction method–which involves splicing genes from extinct animals into the genomes of their living relatives–just might work.
“Just making a DNA change isn’t that meaningful. Splicing mammoth DNA into elephant cells is only the first step in a lengthy process” says Church. “We want to read out the phenotypes.” In order to do that, Church’s team would need to figure out a way to convert the hybrid cells into specialized tissues and test their behavior. For instance, do the mammoth hair genes lead to hair that’s the right color, length, and woolliness? This would be followed by growing the hybrid cells in an artificial womb, which if successful would give rise to hybrid elephant-mammoths which would require temperature sensitization in cold climates. Later, after the engineered elephants gain a foothold, Church says the team will try to revive the mammoths by integrating higher amounts of mammoth DNA into the hybrids.
There are obviously numerous ethical concerns about bringing an extinct animal back into the ecosystem. Church argues that “reintroducing these animals into ecosystems in Russia could actually have a positive impact on Siberian permafrost, which is gradually receding with climate change”. Dr Tori Herridge, an expert in mammoth anatomy from the Natural History Museum, asked “whether or not the justifications for cloning a mammoth are worth the suffering, the concerns of keeping an elephant in captivity, experimenting on her, making her go through a 22-month pregnancy, to potentially give birth to something which won’t live, or to carry something which could be damaging to her. And all of those aspects… I don’t think that they are worth it; the reasons just aren’t there.”
Professor Alex Greenwood seems to agree “We face the potential extinction of African and Asian elephants. Why bring back another elephantid from extinction when we cannot even keep the ones that are not extinct around? What is the message? We can be as irresponsible with the environment as we want. Then we’ll just clone things back?”
More on this can be read here.