Making Chickens Lay Falcon Eggs: The Science of De-Extinction

Have you ever dreamed of snapping pictures of a live wooly mammoth at the zoo? Perhaps you could buy a mammoth wool beanie in the gift shop afterwards, or pay a little extra for a ride on the mammoth's back.
And maybe you've thought, "Science has come so far now ... why not try cloning a mammoth? We have the technology, let's do this thing!" You're not alone in those thoughts. In fact, there's a dedicated group of scientists working on this technology of "de-extinction". And they've made some astounding progress ...

Who is Working on De-Extinction?

First, let's meet Stewart Brand. He recently gave a TED talk on this very subject. Take a few minutes to watch it, and then we'll get into the science a bit.

Here's a quick overview of the interesting points from this video (in my humble opinion):

• There's a nonprofit organization dedicated to bringing back extinct species called The Long Now Foundation. They also help to arrange meetings of scientists who work in the field of "de-extinction". They're going to start with a smaller project than the wooly mammoth, but the big furry guy is certainly a goal down the road.
• There has already been a successful de-extinction: the Bucardo from Spain.
• Some interesting science is available for bringing back extinct species: "Making Chickens lay falcon eggs" and "Reassembling Extinct Genomes"

Reassembling Extinct Genomes

Remember that a genome is all the DNA inside an organism. Your DNA contains the instructions to make you, fido's DNA contains dog instructions, sugar beets contain sugar-beet DNA instructions, and so on (you can refresh your memory about DNA here). So, in theory, if we can get the DNA for an extinct animal, a wooly mammoth perhaps, then we would have the instructions to build a new wooly mammoth. Just like Jurassic Park. Well, you'd be right. 

The only problem is that DNA doesn't store very well. Once the animal dies, it doesn't take long for the DNA to fall apart. That's why, in the movie Jurassic Park, the scientists have to get dinosaur DNA from the mosquitos trapped in amber. In amber, there were no bacteria or oxygen to destroy the DNA. In normal dino bones, the DNA rots away. In modern labs, researchers store DNA in a freezer at -20 C or even -80 C so that it won't fall apart.

But, sadly, most DNA that we have for extinct animals was not carefully preserved in a -80 C freezer. It's often stored in museum specimens or taxidermized skins. The DNA is still there mostly, just fragmented and falling apart.  The solution that smart scientists (like George Church) have come up with is not to use the broken DNA by itself. Instead, they find a living relative of the extinct species (a Mammoth is most closely related to an elephant, for example). Use the healthy DNA from that living relative, and then replace the healthy DNA with fragments from the extinct DNA. Over time, by replacing fragments, you can reconstruct the extinct DNA using healthy DNA as the base. 

Once you have a healthy genome, then all you have to do is clone the species. That means you take a healthy egg from a female of the closest related species, replace the nucleus with your new genome, put it back in the momma, and wait for your healthy baby mammoth to be born (for a bit more on cloning refresh your memory here). Obviously, it's a difficult process, but it's been done with other animals, and it's only a matter of time until those baby mammoths are prancing around the San Francisco zoo.

Making Chickens Lay Falcon Eggs

Closely related to cloning is another process discovered in the lab of Michael McGrew (see their publication). Their technology only works for birds right now, and you still have to start with a complete genome for your extinct bird species. 

Then the cool part: the researchers change the DNA in the reproductive cells of two chickens (a male and a female ... as you probably guessed) to the new genome. When those chickens grow up, the eggs they lay will be for whatever the new genome has instructions to make. In other words, falcon DNA in, falcons out. 

That is dang cool science.