I've seen a few movies where dinosaurs are cloned using "state-of-the-art" techniques. Are any of these scenarios possible? Are they biologically realistic?

-A curious adult from California

January 11, 2007

Those are great questions! The quick answer is that scientists cannot clone ancient beasts right now. And for reasons I'll go into, they may never be able to.

Well why not? Scientists have certainly looked at and studied ancient DNAs. They've looked at insect DNA from 120 million years ago. And some DNA presumably from an 80 million year old fossil may have even come from a dinosaur.

The problem, though, is that there is so little of this DNA. With DNA that old, you tend to get little bits and pieces. There isn't nearly enough of it to make a clone.

The way they got around this problem in the movie Jurassic Park was to sort of fill in the missing bits with frog DNA. The idea I suppose is that you could just copy and paste the dinosaur DNA into the right places in the frog DNA like editing a text file.

At first this might not seem unreasonable. Like a Word document, DNA is a series of letters. But it is important to realize that DNA isn't like a Word document in any other way.

The DNA in a single cell is 30 or 50 (or even more) copies of inches long, invisibly thin molecules with millions and millions of letters that we can't see. There is no way to just Control F and then edit.

You have to find the right spots with hard-to-do biochemistry. Doing it once is hard enough. But over and over again? Very unlikely.

But let's say by some miracle we could get a whole set of Triceratops DNA. Or fill in some frog DNA with mostly Triceratops genes. Or make the DNA from scratch from all the little bits we find. Then could we clone a Triceratops? Again, I am afraid not.

Just sticking DNA into an egg won't work. As we talked about in a previous answer, the DNA has to be in its natural habitat -- the nucleus.

But let's say we somehow overcame this and managed to get a dinosaur nucleus. Or we're able to put the DNA we make into one. Would this be enough? No, not yet.

We need to put the nucleus into a cell. That's possible. In fact, that is how cloning works right now.

But we don't have an entire dinosaur cell. That means we need to use a cell that is around today.

Cells contain more than just DNA. Our bodies are made up of trillions of cells. You can picture each cell as a house with lots of rooms. And each room has a different purpose.

Our cells have DNA in two different rooms. One room contains most of the instruction manual -- the DNA -- that makes us who we are. This room is called the nucleus.

We also have a bit of DNA tucked away in our mitochondria. These instructions are important for building the equipment for making energy.

Imagine that we stick dinosaur DNA in its nucleus into a modern day cell. One kind that I've seen on TV is a frog cell.

Once the nucleus (the DNA) gets into the cell, it needs to talk to the frog mitochondria. But in 65 million years, things change. A frog mitochondria may not interact with a cell (and a nucleus) the same way that a dinosaur one did.

In essence, the two may speak slightly different languages. The end result would be a cell that may not be able to grow because it can't make energy.

Think about it like this. Imagine the nucleus uses the metric system and the mitochondria the American system.

As anyone who wants to figure out what 112 degrees Fahrenheit is in Celsius knows, this can get confusing pretty fast. It's easy to see how things might get mucked up.

Sort of like what happened with NASA. They sent a probe to Mars and forgot to convert something from American to metric. The end result? The probe crashed into Mars instead of orbiting it.

Something similar might happen with the nucleus and mitochondria conversation. When the dinosaur nucleus tries to talk to the frog mitochondria, they may not be able to understand each other. And since the nucleus and mitochondria need to communicate with each other to build the machinery for making energy, the cells wouldn't be able to grow.

To have a shot at cloning a dinosaur we would probably need both dinosaur mitochondria AND a nucleus. Now let's say by some miracle we pulled that off. Could we clone a dinosaur then?

I can't say for sure, but I suppose it might be possible. What I do know is that cloning a dinosaur would be REALLY HARD.

And now that you know more about cells the next time you see a movie that tries to clone dinosaurs you can be the first to tell your friends: THAT WON'T WORK! And you'll be able to tell them why.

Dr. David Skibbe, Stanford University

Cat cloning? Yes. Dinosaur cloning? Not now. Maybe never.

To clone a dinosaur, we might need its mitochondria.