Why haven't we cloned extinct animals?

June 1, 2006 12:17 PM

Why haven't we cloned extinct animals?

Although controversial, cloning is a very interesting topic. I know we have succeeded in cloning a sheep, cat, and some other "regular" animals, but why haven't we cloned extinct animals? Recently they found soft tissue in a T-Rex skeleton and they tried to extract DNA for cloning, but it was too old. They are also trying to clone wooly mammoths for an ancient park not unlike Jurassic Park (pleistocene park, read up), but they are having trouble extracting DNA from the old frozen mammoth they discovered recently. My question is, why not try to clone recently extinct animals such as the Dodo or the giant-bird Mao? Their DNA is so much younger compared to a dinosaur's, so why not start there?

posted by lain to Science & Nature (19 answers total)

Where's the fetus going to gestate? Are you going to keep it in a box?
posted by sohcahtoa at 12:25 PM on June 1, 2006 [1 favorite]

There's a very good explanation here.
posted by cerebus19 at 12:27 PM on June 1, 2006

Or in short, unless we have samples specifically preserved for this kind of thing, cloning is probably going to be impossible.

For that matter, our record of mammal cloning has been extremely difficult, with some species harder than others.
posted by KirkJobSluder at 12:43 PM on June 1, 2006

...or the giant-bird Mao?

Moa. Mao was a giant mammal.
posted by pracowity at 12:45 PM on June 1, 2006 [2 favorites]

Didn't Mao clone himself, anyways?

The Audubon Institute has done some work on extinct cats, since the current species serve as acceptable hosts.
posted by Mr. Gunn at 12:57 PM on June 1, 2006

Genomic DNA, the kind that can form an animal, is fragile. There is a large difference between getting an entire functioning genome and enough DNA to identify something.

So assuming you get the genome out whole, you've got to put it in something, like an ovum. Then you've got to get that ovum to replicate. That is no small task and you aren't even talking anything identifiable as an animal yet.

So let's assume you get to the point of creating a fully functional animal. Then what? There are no other animals of the species with which it could reproduce and the DNA you used was probably very damaged, so its life expectancy isn't very great. Even if you could find two separate genomes and create two animals of different sexes, the next generation would result in inbreeding and it would only get worse from there.

So you've spent several million dollars to create an animal that will die very quickly and won't be anything more than a scientific novelty.
posted by 517 at 12:59 PM on June 1, 2006 [1 favorite]

Also, there are structures (like the mitochondria) in the egg cell from the mother that are necessary to form the new organism and are not encoded in the DNA of the animal. So not only do you need to have the DNA of the organism, you'll also probably need a viable cell to host it. This was do-able with dolly the sheep, just find another sheep and get an egg cell. It maybe a little bit tougher for something like a dodo, let alone a wooly mammoth.
posted by gus at 1:15 PM on June 1, 2006

Previously.
posted by mattbucher at 1:26 PM on June 1, 2006

"So you've spent several million dollars to create an animal that will die very quickly" but will teach you a lot about that species while it is alive. How did dinosaurs behave? There is lots of good speculation and some evidence (footprints, etc.), but it would be nice to see a few of them running about together.

I'm not saying cloning something from that long ago is possible, but if it were possible, I don't think people would or should hold back just because the thing wouldn't be able to reproduce and maybe would be a bit expensive. If you could create a few of them and let them live out a fairly natural life -- maybe on an island? yeah, an island! a remote, uncharted island! completely, safely isolated from the rest of the world! -- you wouldn't be hurting them and you certainly would be increasing our knowledge of prehistoric life.
posted by pracowity at 1:29 PM on June 1, 2006

Response by poster: Yes, I was also wondering where a dinosaur embryo would grow, because nothing exists today that can "house" such a massive egg.
posted by lain at 1:31 PM on June 1, 2006

There are researchers in South Africa trying to resurrect the extinct Quagga through Zebra breeding. Quagga DNA has been extracted, but the technology to build a healty offspring does not exist.
posted by Alison at 1:42 PM on June 1, 2006

But how about a wooly mammoth, implanted in an elephant to gestate? And once we get a breeding population of them, selling mammoth meat at Walmart? How far are we away from that?
posted by LarryC at 1:44 PM on June 1, 2006

They've been trying to with the Tasmanian Tiger, as they thought viable samples existed. I believe, however, the project has been abandoned.
posted by [insert clever name here] at 2:02 PM on June 1, 2006

"...but will teach you a lot about that species while it is alive. How did dinosaurs behave..."

The point of my statement was that someone will have to pay for the development of the animal. Coming across millions of dollars to create something that couldn't possibly earn enough money to break even on is no small feet. In fact it is probably one of the larger obstacles along the path.
posted by 517 at 2:10 PM on June 1, 2006

But how about a wooly mammoth, implanted in an elephant to gestate? And once we get a breeding population of them, selling mammoth meat at Walmart? How far are we away from that?

IANA biologist either, but I've done lots of reading.

My understanding is that DNA is not a blueprint. It's more like a recipe, i.e. instructions for a process rather than a description of an end result. The process that DNA goes through in building an organism is inextricably tied to the environment (i.e. the host/womb) where the process takes place. Section X of the DNA might display behavior Y when it encounters a certain chemical gradient, then switch to behavior Z when it encounters a different enviroment. If the host womb is a whole different species, then the enviromental cues will be different that normally encountered by the DNA.

Therefore, even if elephants were sufficiently genetically close to make gestating a mammoth clone possible, we could never be sure that the result was exactly like a "real" mammoth would have been.

For extinct species (such as dinosaurs) which have no close living relatives, the problem would be even greater.

In addition, all the technical problems listed by other posters still remain to be solved.

(If any actual embryologists are reading this, please correct any misconceptions in this post.)
posted by tdismukes at 2:36 PM on June 1, 2006

Response by poster: b1trot, I guess you are right, it isn't a #1 priority because we haven't mastered cloning existing animals yet.

tdismukes, you really explained that well, thanks. I guess we will never know what a real mammoth tastes like =P

I think it would be worth the money to end up with an organism long vanquished from the earth. It would be such a big event.
posted by lain at 2:55 PM on June 1, 2006

A large chunk of the reason is that cloning stuff is really really expensive, and most threatened species programs fail from a lack of funding, so we would have absolute rocks in our heads to start wasting money on trying to clone a couple of species while at the same time letting heaps of others disappear.

Gene banks have been and are being set up, so that maybe in 50 years when we don't have any threatened species left, only the common ones, and we know more about cloning, we can tehn start to repopulate the world.
posted by wilful at 7:52 PM on June 1, 2006

lol, sohcahtoa
posted by Afroblanco at 7:01 AM on June 2, 2006

I'm 13 so I know my answer might be too simple. But the first thing I thought was that there's a reason it has gone extinct. I have a friend who has a herd of an extinct (in its nat. environment) animal on his ranch. It's genetically pure stock and I think there are like, about a hundred of them. He has gone to Africa twice to try to re-establish this species but so far he can't cuz there isn't enough proper habitat that wouldn't leave an unestablished herd safe from predators, and no one will put up the fences to help them stay safe for a while until they are established. Habitat loss, the introduction of exotic species, pesticides, pollution, population and overhunting/over fishing are humongo reasons why a lot of species go extinct in the first place. If you COULD bring a species back, like a dino or a mammoth, you would be introducing an exotic species into wherever you put it because the eco system wouldn't be adapted to this new animal. So by doing this, you could be sort of "saving" one species and destroying a whole entire eco-system. And I wouldn't sacrafice the possiblities of what we could learn on an island, for the sake of an experiment like that. But it's true: I'd kinda like to see a mammoth. I have a mammoth tooth and it's really kewl.
posted by FeistyFerret at 6:43 PM on June 3, 2006