Scientists have long believed that a universal genetic code serves as a blueprint for all life on Earth, dictating the structure and function of organisms from the simplest bacteria to complex humans.

Despite awe-inspiring diversity, nearly every lifeform—from bacteria to blue whales—shares the same genetic code. How and when this code came about has been the subject of much scientific controversy.

"The genetic code is this amazing thing in which a string of DNA or RNA containing sequences of four nucleotides is translated into protein sequences using 20 different amino acids," said Joanna Masel ...