Target 4 - mRNA Codon Chart To use the mRNA Codon Chart, you must have a strand of mRNA. So, if you are given DNA, you must first convert to mRNA. DNA Base Matching mRNA Base A U T A C G G C Target 4 - mRNA Codon Chart Each codon is a three-base “word” such as AUG, CTG, UUA, etc. Each codon matches to a specific amino acid that can be found on the codon chart shown to the right Target 4 - mRNA Codon Chart If a codon is ACG, you find the first letter (A) on the left side of the chart. That tells you the general row. Then find the second letter (C) on the top, that tells you the column. Then find the third letter (G) on the right, that shows you which specific amino acid. In this case, ACG = The amino acid “Thr”