How prebiotic chemistry evolved on early Earth

New York Times : The formation of the biomolecular building blocks of life on Earth is the focus of a recent study by John Sutherland of the University of Cambridge and colleagues. First the researchers spent a decade trying to form RNA, thought to be the first information-carrying molecule of life, from prebiotic chemicals. What they discovered was that although RNA is composed of a base, a sugar, and a phosphate, there was no natural way to join the sugar and base together. However, using the same starting chemicals, they were able to build an intermediate molecule—part sugar, part base—and join that with a phosphate to form a ribonucleotide. Having found that key chemical turning point some six years ago, the researchers then turned to the question of how the chemical precursors to RNA may have first formed on early Earth. They propose that during the Late Heavy Bombardment , when a cascade of asteroids collided with Earth, carbon from the asteroids reacted with nitrogen in Earth’s atmosphere to form hydrogen cyanide, and it is from that chemical soup that early sugars and other chemical precursors of life may have formed.