Eight-letter genetic code hints at how alien life might evolve

Researchers have created an ‘alien’ genetic code made out eight bases instead of the usual four. The expanded genetic alphabet shows how life could arise if organisms never evolved proteins but instead relied on RNA as their biomolecular workhorse. Life on Earth is built around proteins: they catalyse biochemical reactions and provide cellular structural elements. DNA, on the other hand, acts as biological information storage unit, while RNA provides a link between the two.