Beth Shapiro is associate professor of ecology and evolutionary biology at the University of California, Santa Cruz. Her work has appeared in numerous publications, including Nature and Science, and she was a 2009 recipient of a MacArthur Award. Her new book How to Clone a Mammoth: The Science of De-Extinction was named One of Flavorwire’s 10 Must-Read Academic Books for 2015.
This interview first appeared on Five Books.
Beatrice Wilford: How does de-extinction differ from what we see in Jurassic Park, i.e. the re-creation of whole species for the enjoyment of humans?
Beth Shapiro: De-extinction is not possible, to start with. Jurassic Park is particularly not possible. The premise of Jurassic Park was that DNA was preserved in mosquitos, that were somehow preserved in amber. The scientists at this crazy park were then able to extract dinosaur DNA from mosquitos and sequence bits and pieces of that DNA and fill the missing parts in with frog DNA (which is another thing I don’t really understand because even at the time we knew that birds were more closely related to dinosaurs than frogs are). All of that is not possible, DNA is not preserved in amber and DNA from dinosaurs is 65 million years old. It is much too old to actually be preserved. The oldest DNA that we’ve ever been able to recover was from a horse bone that was preserved frozen in the arctic soil and it was about 700 thousand years old. And the only reason we were able to get DNA from something that old was because the bone was frozen pretty much immediately after death and stayed that way.
De-extinction, the idea of bringing a species back to life after it is gone, extinct, would require cloning. That requires a living cell. Once an animal is dead, there aren’t any living cells in its body. The DNA starts to be broken down right away by water and oxygen and UV light and by microbes living in the soil chewing up the DNA. That’s not possible.
How might we bring something like a mammoth back to life? It’s not possible and it’s also ethically probably a terrible idea, but let’s pretend that’s not true for the moment and say how would we do it. We would take an elephant cell. Importantly, elephants and mammoths are a very closely related species. They have a common ancestor about six million years ago and elephant DNA is already 99% identical to a mammoth’s. So all we have to do is take that living elephant cell and swap out that remaining 1%, switch the DNA from the elephant version of that DNA to the mammoth version of that DNA, and there are genetic tools that are available today with which one could do that.
That’s where we are with de-extinction and, in fact, we now have complete genome sequences from a couple of mammoths and scientists have started to make lists of genes that are different between mammoths and Asian elephants. There’s even a lab at Harvard, headed by George Church, where they’ve used these genome-editing tools and swapped out fourteen genes. They have elephant cells growing in a dish in a lab that have fourteen mammoth genes, so they are mammoth-like cells. But that’s a very big difference: having cells growing in a dish and having an actual animal. Getting the rest of the way is something we can’t do, yet. And ethically is probably a terrible idea. But that is the process that one might use to bring a mammoth back to life.