Geneticists are scientists who study genes. Our genes make up our DNA. They tell specific parts of the body how to grow and work. Scientists use their knowledge of genes to cure diseases. They also try to slow the effects of growing old.

A team of scientists is using genes to try to bring back the woolly mammoth (Mammuthus primigenius). The woolly mammoth was an animal that lived in the Ice Age. It looked like a hairy elephant. The last mammoth died about 4,000 years ago.

Ben Mezrich wrote the book "Woolly: The True Story Of The Quest To Revive One Of History's Most Iconic Extinct Species." He followed scientists who are trying to bring the woolly mammoth back to life.

National Geographic talked with Mezrich. He explained why some people think woolly mammoths could help fight climate change. He also talked about concerns over making new woolly mammoths.

Bringing back a woolly mammoth sounds like something out of the movie "Jurassic Park." Is it really happening?

It is! The stuff in "Jurassic Park" is now possible. We have new genetic tools. It used to be that we were just reading DNA. Now we are at the point where we can write it too.

The world in which we live is going to be a different place in 30 years. People talk about the Internet or robots changing the world. I believe biology, the study of living things, is going to be even more important.

A geneticist named George Church wants to revive the mammoth. Describe him and the project he is leading.

"He’ definitely looks like he could be in a movie. He’ is almost 70 years old,” with this enormous beard and white hair. He grew up in Florida. He was raised by a single mother. Starting at the age of 12, Church started to think he was someone who had come from the future.

He’ is like a modern Einstein. He has come up with faster ways of mapping and reading human genes. His lab has been working for the Woolly Mammoth Project. This is a group that wants to bring the mammoth back to life.

The other part of the Woolly Mammoth Project is in Siberia, Russia. Tell us about the scientists Sergei and Nikita Zimov.

The big question is, why make a woolly mammoth? One answer is in Russia. The Siberian plains are huge grasslands in the north. They are covered in permafrost. It is a sheet of ice that has been frozen for thousands of years. There are fewer animals than there used to be.

Carbon gets trapped inside the permafrost. If the carbon gets freed, it stays in the air. It traps heat, making the world hotter. The problem is that the world is warming already. If the permafrost melts, all the carbon will be let loose.

Sergei Zimov and his son, Nikita, are Russian scientists. They have been doing an experiment. They blocked off a part of the plain. They brought back animals that lived there long ago. They brought reindeer, bison and Yakut horses.

Sergei and Nikita Zimov discovered that animals make the permafrost cooler. They made the temperature fall by as much as -9.5 degrees celsius (15 degrees Fahrenheit). That is because large plant-eaters help grasses to grow. These light-colored grasses reflect sunlight back into the air. They act like a mirror. By sending back light, they send back the sun's heat. This makes the temperature go down.

Adding mammoths would be helpful. They would help to keep the temperature down along with the other animals.

You wrote there are many mammoth bones in Siberia. People are digging them up to take their tusks. Tell us about that.

The permafrost is slowly melting. Woolly mammoths are showing up there all the time. The tusks are worth about $250,000 dollars each.

Selling elephant tusks is against the law. But selling mammoth tusks is OK. The mammoth is not an endangered species. It is already extinct.

The Yakut people are a native group there. They go out in boats across frozen water. They get to tiny islands where there are many mammoth bones. Then, they dig up the tusks. If they find one, they can get all the money a Yakut village needs in a year.

What are the difficulties in creating a woolly mammoth? When will we see the first one?

The science is really cool. Frozen animal remains are brought up from the ice. Then you take a piece and map out its genes. Once you’ have got them, you choose the genes that only a mammoth has. Nearly all of their genes are the same as those of an Asian elephant. Church's lab believes that a woolly mammoth and an Asian elephant could have a baby together.

First, you create the mammoth genes in a lab. You place them into the embryo of an Asian elephant. The embryo is a small group of cells. It grows into a baby. The embryo gets put back into an Asian elephant. Then, the Asian elephant gives birth to the baby woolly mammoth.

Church's lab is also working on a man-made womb, which could hold the baby woolly.

Making new forms of life in labs might look like trying to play God. Is it moral?

That's a great question. You have to really think about these things before you actually do them. Science can move fast without thinking about what is right or wrong.

In this case, I believe— that bringing back an extinct species is is like fixing something we did. Also, scientists play God every day. We try to cure diseases, for example. That means we change lives in a big way.

The scariest thing i’s that no one is really checking. There are labs all over the world that work on genes. Most scientists think that someone should be checking their work. It could be scientists themselves, or the government. Either way, there should be rules.

At the end of the book, it says a Korean-Russian team found a frozen mammoth. They said it still has blood in its veins. Is that really true?

The Korean company Sooam Biotech says it found this mammoth. The boss of this company has been caught lying about science before.

They are working with a Russian team. Together, they say they found a woolly mammoth half-covered in ice. It was in very good condition. When the team pulled it up, the body still had liquid blood in it, they said.

It is hard to say if this is true or not. The animal's body is hidden away in a Russian university. If there is liquid blood, maybe you can use it to copy the DNA. Then you could build a mammoth.

George and his team do not believe it is possible. But who knows?