RNA strands are formed from building blocks called nucleotides linked together head to tail in a long chain. This happens easily if the nucleotides can bind to another RNA strand that guides their assembly. However, the earliest RNA molecules to form, billions of years ago, would have had no pre-existing RNA to guide them.

Till now, attempts to mimic this first synthesis have always hit a fatal obstacle: instead of binding to the tail of a new nucleotide, the head of a growing chain latches onto its own tail instead. This tendency to form circles keeps RNA molecules from growing much longer than three to six nucleotides – far too short to function as enzymes.

"That is a big problem," says Nicholas Hud, a chemist at Georgia Institute of Technology in Atlanta. "How do we get a molecule long enough to do something interesting?"

The Costa Rican healthcare system is rated very highly on an international level, and the country’s citizens enjoy the health and life expectancy equal to that of more developed nations. These accolades come courtesy of strong, universal health insurance and excellent public and private hospitals.

Public Health Care - Caja Costarricense de Seguro Social (CCSS)