This photo shows Martha (right), an extinct passenger pigeon, at the Smithsonian's Natural History Museum in Washington, D.C. Once the most plentiful bird on the planet, the passenger pigeon became extinct in September 1914 when Martha died at the Cincinnati Zoo. Photo: AP Photo/Susan Walsh/MCT

One hundred years ago, the last passenger pigeon died. Her name was Martha, and she lived alone in a cage in the Cincinnati Zoo.

There used to be more than 3 billion passenger pigeons in the world. After Martha died, there were zero.

###### There were no more of that species, that kind of animal.

There have been no passenger pigeons since 1914. Maybe that can change now. Some scientists are trying to bring back the passenger pigeon.

######

DNA is a set of instructions on how to make a particular animal. DNA forms genes, which control how an animal is made - will it have wings or arms, blue feathers or red hair or brown fur?

Something Called De-Extinction

If an animal's genes could be recreated, maybe a long-lost species could be brought back to life.

That's the idea behind something called de-extinction.

It works like this: take DNA information from an extinct animal like Martha. ######

Then, try to grow a baby bird in an egg from the living pigeon.

If all goes well, a copy of the long-lost Martha could hatch. One new bird would lead to another, and another. One day, large flocks of passenger pigeons might be seen flying in the skies.

###### His goal is to bring back the passenger pigeon.

Novak is studying genes taken from dead passenger pigeons. At the same time, he is studying the genes of a related bird: the band-tailed pigeon.

"Sequencing A Genome"

So far, 32 passenger pigeon samples have been studied. ###### A "genome" is the complete set of genes found in a certain animal. "Sequencing" means figuring out the order of the genome's parts.

Sequencing the genome allows scientists to figure out which genes make a passenger pigeon a passenger pigeon.

The samples Novak is studying will also help him figure out something else: how the bird lived in the wild. Understanding that will help him decide if a restored passenger pigeon would do well in today's woods.

###### Nothing is telling him to "turn back now and not bring back the passenger pigeon."

If the de-extinction works, there would still be one remaining challenge: Teaching the new birds how to be passenger pigeons. Doing that could be very difficult. The new birds would be part band-tailed pigeon. ###### It would be up to humans to show them what to do.

Still, if everything goes well, Martha may no longer be the last of her kind. Ten years from now, passenger pigeons could be flapping around once again.]]>