Chemistry grant takes aim at life’s origins

How did we get here? How did life spring to Earth four billion years ago?

Portland State chemistry professor Dr. Niles Lehman has been awarded a $600,000 grant from the John Templeton Foundation to answer these questions. Lehman and his lab are examining the way certain chemicals connect with each other to form complex—and eventually self-replicating—networks of molecules that could have led to life on Earth. Life, as stated in a paper Lehman published in April 2016 with former Ph.D. student Jessica Mellor Yeates, is “a self-sustaining chemical system capable of Darwinian evolution.”

Lehman, a professor at PSU since 2001, said the grant was awarded in mid-December but he has recently started to receive some of the funding. Lehman has received smaller research funds for projects from the Templeton Foundation in the past, but when he heard the organization was looking at big questions regarding the genesis of life, he decided to apply for this grant.

“They recently decided to put funding toward finding the chemical origins of life,” Lehman said. “I thought our research was a good fit.”

A press release covering the grant announcement said Lehman has been working on this research for 25 years and he has previously received funding from NASA to work on these projects.

“The money only goes so far,” Lehman said.

According to Lehman and Yeates’ paper, different studies over the past century have demonstrated the ability of ribonucleic acid—or RNA—to arise from mere chemicals. The paper cites experiments in which scientists have created chains of nucleotides (subunits of nucleic acids like RNA). These lab-created chains are longer than what is naturally needed to have arisen spontaneously on primitive Earth.

But there’s a catch: Scientists have not quite figured out how the chains can self-replicate on their own outside the lab. There is a big difference between molecular networks created one at a time in a lab and even the simplest self-replicating life forms occurring in nature. The path between those first chemical steps and current cellular self-replication is what Lehman’s research seeks to uncover.

Lehman says there are many theories as to how life arose on earth, but the dominant theory is called RNA world.

“The idea states that the first living molecules were RNA—somehow RNA formed spontaneously,” Lehman said. “Once it formed, it demonstrated the rudimentary ability to evolve and take on lifelike features.”

Eventually, RNA molecules could trade chunks of genetic information, allowing them to mutate and develop. According to the press release, Lehman thinks these chemical connections between RNA molecules could have evolved to cooperate in a more efficient and structured manner as time went on.

There are many other labs and scientists studying how these molecular systems, these building blocks of life, generated spontaneously. Lehman said that his research picks up where the other research leaves off.

“We are looking at the stepping stones between chemistry and the type of biology that most people are familiar with,” Lehman said.

Lehman said that his lab of five doctoral graduate students and two undergraduate students “are essentially evolutionary biologists working in a chemical setting,” and that there are actually many parallels between ecological communities outside and the molecular communities his lab observes in glass tubes. These tiny environments experience things like succession and even invasive species—only in a chemical sense rather than how we normally think of species.

“A molecular species is basically an RNA sequence,” Lehman said. “Whereas an organismal species is a cellular entity with a whole diversity of molecules inside it, not just one.”

According to the paper Lehman and Yeates published in April, something the lab hopes to explore in future research is how these small molecular networks demonstrate heritability, or a measure of how a species can evolve when placed within natural selection.

“It’s the nature part of ‘nature versus nurture,’” Lehman said.

Lehman also asserted that every trait of a species is due to a combination of genetic makeup and external environmental factors. Heritability is how much of that given trait is due to genetics;
figuring this out will help his group uncover how RNA can evolve naturally, perhaps even into self-replication.

“There had to be some pre-Darwinian evolution or a chemical evolution that set up the traditional ‘survival of the fittest,’” Lehman said.

The Templeton grant will allow the Lehman lab to study these molecular networks, examine more closely how they evolve and hopefully bridge the gap between life’s generation and self-replication, answering one of science’s biggest questions.