George Church grew up by the mudflats in Clearwater, Florida, where his school didn’t even have a science teacher until he was in seventh grade. But he was always fascinated by nature, and "interested in sort of random experiments, like burning things with magnifying glasses — the kind of things kids do."

In his case, the hijinks arose from an irresistible drive to understand. "To me, everything had to be explained," he recalls. "I was a little compulsive, maybe."

When Church was 10 years old, he traveled the farthest he’d ever been from his Florida home, to the 1964 World’s Fair in New York. There, he saw a vision of what the future could be like.

"And that was extremely motivating for me," he says. "I decided, in some sense, at that moment, I was going to help create that future, whatever it took."

Church, of Harvard Medical School, is 62 now, a towering man of 6-foot-5 with a full white beard, famous as one of the world's more brilliant scientists and on this year's Thomson Reuters short-list for the Nobel Prize in chemistry. And he has helped create that future.

It’s a future that few could imagine back in 1964: a world where humankind not only decodes its own genes but is beginning to alter them, even to make them, in the lab.

Church has long been at the forefront of this new gene era -- working to figure out how to sequence or "read" DNA better and faster and cheaper. How to "write" DNA, or build it from scratch. And how to modify genes with a powerful new tool called CRISPR, a sort of a molecular scissors used to cut and edit specific genes.

In just three years, CRISPR has swept through biology labs around the world, turbocharging research on everything from cancer to better food crops.

"It really seems to be unstoppable," Church says. "That said, there are possible improvements. But it is taking the world by storm."

CRISPR is widely expected to earn at least one of its pioneers a Nobel soon. Church and colleagues were the first to show how it could be used in human and mouse cells; hence, his place on the Nobel short-list this year.

'Telling The Muggles'

Church stands out not just for his science but for his willingness, even eagerness, to talk about it — what it could mean, how it could go wrong — with the public.

"When I say he’s a visionary, it’s not just in terms of what is technologically possible," says Kevin Esvelt, a mentee and colleague who leads the Sculpting Evolution group at MIT. "George actually attempts to think about what the consequences are, and not just for his field." And "he delights in telling people, because he thinks people have a right to know, and should be thinking about this much more."

So, for example, way back in 2005, Church publicly posted his own genome -- the full set of his genes -- in an early demonstration of what our personal gene information can tell us.

He's prominent in the ongoing debate about whether we should use CRISPR to change human genes in ways that could be passed down to future generations. And his most recent public splash was his proposal this summer to synthesize a whole human genome in the lab — not to create a human but to use as a tool for developing treatments for human disease.

Church in his office at Harvard Medical School (Alison Bruzek/WBUR)

This radical openness draws criticism from some other researchers, Esvelt notes; some scientists see non-scientists as a bit like the non-magic people in Harry Potter, and their attitude is: "Don’t tell the Muggles!"

But Church so believes in telling the Muggles that he even braves the (friendly) jibes on "The Colbert Report": "Are you playing God, sir?" host Stephen Colbert demanded in 2012. "Because you certainly have the beard for it!"

Church's wife, Ting Wu, who leads her own Harvard genetics lab, says he works hard to share genetic discoveries with the public out of a deep sense of responsibility, and "to ensure that science stays in touch with the people it serves."

"In his book," she says, "the more one shares, the faster and safer the progress, the better off we'll all be."

'Killer Virus Or Mutant Squid'?

Safety is a key element here. Church talks about potential wonders from genetic engineering, like using bacteria to power cars. But what if we monkey with nature and something goes very wrong?

As Colbert pointedly asked him: "How do you think your work will eventually destroy all mankind? Couple of options: Do you think it’s going to be like a killer virus or more like a giant mutant killer squid man who arises from the Pacific between Easter Island and Chile and feasts on our flesh?"

Colbert makes it comic but Church takes questions of safety very seriously: "I would say that I worry about everything," he says. "I’m one of the top world worriers."

As a consequence, he says, "A lot of our innovative energy is focused on safety, security and communication with the public so that we can get lots of voices -- not us talking at them but listening to each other about ways that things could go wrong."

A concrete example: Church is backing Esvelt’s proposal to genetically engineer mice on Nantucket and Martha’s Vineyard to fight Lyme disease. The science is still in progress, but already, Esvelt has broached the idea to public meetings on the island, and in the media. And he’s developing ways to undo or limit the gene changes.