One tiny chemical difference between RNA and DNA may help explain how life began

Scientists may have found a clue to one of the biggest mysteries surrounding the origin of life: how fragile RNA molecules could gather and survive before cells existed. New research shows that RNA is unusually good at assembling into tiny liquid-like droplets that concentrate molecules and can harden into protective, gel-like structures. Remarkably, much of this behavior may come down to a single oxygen-containing chemical group that RNA has but DNA lacks.