News FocusEvolution

The First Codon and Its Descendants

See allHide authors and affiliations

Science  17 Jul 1998:
Vol. 281, Issue 5375, pp. 330
DOI: 10.1126/science.281.5375.330

You are currently viewing the summary.

View Full Text

Log in to view the full text

Log in through your institution

Log in through your institution


A biophysicist looked for common features in messenger RNA molecules to determine which of the genetic code's "words," or codons--the triplets of bases that code for amino acids--came first. He concludes that the first word was GCU (guanine, cytosine, and uracil) and calculates how GCU might have evolved into the current set of 61 codons that specify the 20 amino acids.