Start codons in DNA may be more numerous than previously thought

Yet again, genetics is more complicated than we thought. Start codons in DNA may be more numerous than previously thought

Genetic code is typically represented via sequences of four letters—A, C, G, and T or U—which correspond to the molecular units known as adenine, cytosine, guanine and thymine (for DNA code) or uracil (for RNA code). Fifty years ago, the best available research tools indicated that there were only a few start codons (with sequences of AUG, GUG and UUG) in most living things. Start codons are important to understand because they mark the beginning of a recipe for translating RNA into specific strings of amino acids (i.e., proteins).

NIST specializes in the process of precision measurement, and the start codon challenge proved irresistible to the JIMB team. The collaboration was formed in 2016 with the goal of advancing biomeasurement science and facilitating the process of discovery by bringing together experts from academia, government labs and industry for collective scientific investigations.

With the use of GFP and nanoluciferase, the team measured translation initiation in the bacteria E. coli from all 64 codons. They were able to detect initiation of protein synthesis from 47 codons. The implications of the work could be quite profound for our understanding of biology.