Life on Earth originated in an intimate partnership between the nucleic acids (genetic instructions for all organisms) and small proteins called peptides.
Their “peptide-RNA” hypothesis contradicts the widely-held “RNA-world” hypothesis, which states that life originated from nucleic acids and only later evolved to include proteins.
The new papers — one in Molecular Biology and Evolution, the other in Biosystems — show how recent experimental studies of two enzyme superfamilies surmount the tough theoretical questions about how complex life emerged on Earth more than four billion years ago.
“Until now, it has been thought to be impossible to conduct experiments to penetrate the origins of genetics,” said co-author Charles Carter, PhD, professor of biochemistry and biophysics at the UNC School of Medicine.
“But we have now shown that experimental results mesh beautifully with the ‘peptide-RNA’ theory, and so these experiments provide quite compelling answers to what happened at the beginning of life on Earth.”
The special attributes of the ancestral versions of these enzyme superfamilies, and the self-reinforcing feedback system they would have formed with the first genes and proteins would have kick-started early biology and driven the first life forms toward greater diversity and complexity, the researchers said.