The ELSI researcher investigating one of the greatest puzzles of our existence

A key step to early life on Earth could have started in a primordial pond, repeatedly baked dry by the Sun then refilled by rain, according to a theory being tested.

A researcher at the Earth-Life Science Institute (ELSI) is examining whether the proposed pond, by cycling from wet to dry, imposed a kind of natural selection on the simple chemicals found there, helping drive the emergence life.

One of the greatest puzzles of our existence is how life first began. Modern cells use DNA, RNA and proteins to store and access the information required to build an organism. Nicholas Guttenberg, a complex systems scientist researching origins of life at ELSI, says a system of this complexity could not have evolved in a single step. "By what pathway might it have emerged?" he asks.

Looking at past work on life's origins, he says, it seemed relatively easy to find simple chemicals that can copy themselves. But these systems appeared unable to 'evolve' from generation to generation. "So the idea was to figure out why that seemed to be happening, and if there was a way to fix it," Guttenberg says.

Using a combination of computer simulations and wet lab experiments, Guttenberg and his collaborators are testing the possibility that systems that naturally cycle between two different states, ¬from wet to dry, or from frozen to thawed, for example, could have helped drive the next phase of evolution.

In one computer model, Guttenberg is exploring the idea that combinations of chemicals could pair up to survive the constant switch between states - like a primitive version of DNA base pairing. Chemicals that pair up successfully would avoid being flushed out of the system - and gradually accumulate over successive cycles of wet and dry. In other words, the system should 'remember' these chemicals over time.

What's more, Guttenberg says, membership of this selective set of chemicals should gradually alter over time - evolve, in other words - and perhaps acquire new levels of complexity over time.

"The ability of these systems to remember information is something that emerged piecewise - not just from nothing to perfect memory," says Guttenberg.
"I think getting an index of the mechanisms that sit in the grey zone between simple systems that just replicate themselves, to the full-fledged RNA-DNA replication, is the most important thing to do right now - because maybe then you can chart a course," he says.

Early life may have started in a primordial pond, repeatedly baked dry by the Sun then refilled by rain, says ELSI's Nicholas Guttenberg.

Nicholas Guttenberg is now working at Araya Brain Imaging and contributes to ELSI's study on the origins of life as ELSI Affiliated Scientist.