Oct. 2 (UPI) -- Scientists at McMaster University in Canada have offered a new, detailed explanation for the origins of life.
In the laboratory of early Earth, researchers hypothesize that small, warm ponds served as the Petri dishes in which the great experiment of life began. The chemical spark was provided meteors, which delivered nucleotides to the nutrient-rich ponds.
Researchers conducted a series of calculations -- combining components of astrophysics, geology, chemistry and biology -- to identify the combination of factors most likely to have yielded the first life forms.
"No one's actually run the calculation before," Ben K.D. Pearce, researcher at McMaster's Origins Institute in Hamilton, said in a news release. "This is a pretty big beginning. It's pretty exciting."
According to the latest analysis, the unique wet and dry cycles of small, warm ponds were essential to the perfect combination of chemicals and conditioning. The up and down of precipitation and evaporation, inflows and outflows, primed nucleotides for bonding.
Under the right conditions, newly linked nucleotide chains of RNA polymers began to spontaneously replicate as they pulled in additional nucleotides. Because the polymers were imperfect, they were capable of self-improvement through evolution.
"That's the Holy Grail of experimental origins-of-life chemistry," Pearce said.
The emergence of self-replicating, evolving RNA set the stage for the development of DNA.
"DNA is too complex to have been the first aspect of life to emerge," researcher Ralph Pudritz said. "It had to start with something else, and that is RNA."
The scientists' calculations -- detailed this week in the journal PNAS -- suggests thousands of ponds on early Earth offered the necessary conditions for the emergence of RNA. Warm, dynamic ponds were abundant, and meteorites were striking Earth at a high frequency.
"We're thrilled that we can put together a theoretical paper that combines all these threads, makes clear predictions and offers clear ideas that we can take to the laboratory," Pudritz said.