(Describer) In an animation, streams of light collide to create a globe filled with water. Title: Science Nation. The sun appears over a global horizon.

(male narrator) It's one of the most profound questions: how did life on earth begin?

(male) When I got into science, I wanted to work on a big question, a question that would be interesting all of my life. The more I thought about origin of life, the more I thought, "This really fits the bill."

(narrator) With support from the National Science Foundation, Georgia Tech biochemist Nicholas Hud and a team at the Center for Chemical Evolution are working to chip away at the question. They're homing in on how chain-like chemicals called polymers first came together and evolved 3.5 to 4 billion years ago.

(male) We're thinking that on the early earth, the molecules that gave rise to the first polymers of life, RNA and DNA, would have actually started by small molecules interacting with each other and forming very ordered structures.

(narrator) In other words, they assembled themselves.

(male) In the center of this model are what we call the base pairs.

(narrator) Hud's focus is the RNA molecule, a chemical sibling to the better-known DNA.

(Describer) Animations illustrate.

RNA does the genetic heavy lifting in a cell, translating the information stored in DNA into materials needed to build a living organism. Some researchers believe that RNA, or an RNA-like polymer, was the first molecule of life.

(Describer) Liquid is stirred in a flask.

Hud's team works with chemicals believed present on the early earth.

(Describer) Brian Cafferty:

(male) So we can then select from this chemical inventory the molecules that might have been important for getting something like life kick-started.

(narrator) So far, no labs working on chemical evolution has been able to coax RNA to self-assemble in the lab. But Hud and his team have identified a couple of molecules that make a structure that almost looks like RNA.

(male) They start out by pairing together. Then they stack together. They form structures that go from two to six molecules to twelve molecules, up to the level of thousands, even hundreds of thousands of molecules associated together.

(narrator) Hud says these may be the chemical ancestors of RNA as we know it today.

(male) If we take the components that we have in RNA today and we change them, sometimes just by one or two atoms, we find they react together much more easily. And they seemingly put us on the road towards making what we might call a proto-RNA polymer.

(narrator) Putting chemistry to work, sleuthing out the origins of life. A bit like genealogy, perhaps, but going way, way back on the family tree.

(Describer) A globe turns beside the title.

For Science Nation, I'm Miles O'Brien.