DNA 101: Which codons codes for which protein?
On DNA codons, which codons codes for which protein?
In DNA, codons are specific sequences of three nucleotides that encode for particular amino acids during protein synthesis. The genetic code is degenerate, meaning that multiple codons can code for the same amino acid. The genetic code is nearly universal, meaning that the same codons typically code for the same amino acids across different organisms.
Here is a basic table showing the DNA codons and the amino acids they code for (using the single-letter amino acid code):
| Codon (DNA) | Amino Acid |
|---|---|
| AAA | Lysine (K) |
| AAC | Asparagine (N) |
| AAG | Lysine (K) |
| AAU | Asparagine (N) |
| ACA | Threonine (T) |
| ACC | Threonine (T) |
| ACG | Threonine (T) |
| ACU | Threonine (T) |
| AGA | Arginine (R) |
| AGC | Serine (S) |
| AGG | Arginine (R) |
| AGU | Serine (S) |
| AUA | Isoleucine (I) |
| AUC | Isoleucine (I) |
| AUG | Methionine (M) (Start codon) |
| AUU | Isoleucine (I) |
| CAA | Glutamine (Q) |
| CAC | Histidine (H) |
| CAG | Glutamine (Q) |
| CAU | Histidine (H) |
| CCA | Proline (P) |
| CCC | Proline (P) |
| CCG | Proline (P) |
| CCU | Proline (P) |
| CGA | Arginine (R) |
| CGC | Arginine (R) |
| CGG | Arginine (R) |
| CGU | Arginine (R) |
| CUA | Leucine (L) |
| CUC | Leucine (L) |
| CUG | Leucine (L) |
| CUU | Leucine (L) |
| GAA | Glutamic Acid (E) |
| GAC | Aspartic Acid (D) |
| GAG | Glutamic Acid (E) |
| GAU | Aspartic Acid (D) |
| GCA | Alanine (A) |
| GCC | Alanine (A) |
| GCG | Alanine (A) |
| GCU | Alanine (A) |
| GGA | Glycine (G) |
| GGC | Glycine (G) |
| GGG | Glycine (G) |
| GGU | Glycine (G) |
| GUA | Valine (V) |
| GUC | Valine (V) |
| GUG | Valine (V) |
| GUU | Valine (V) |
| UAA | Stop (Termination codon) |
| UAC | Tyrosine (Y) |
| UAG | Stop (Termination codon) |
| UAU | Tyrosine (Y) |
| UCA | Serine (S) |
| UCC | Serine (S) |
| UCG | Serine (S) |
| UCU | Serine (S) |
| UGA | Stop (Termination codon) |
| UGC | Cysteine (C) |
| UGG | Tryptophan (W) |
| UGU | Cysteine (C) |
| UUA | Leucine (L) |
| UUC | Phenylalanine (F) |
| UUG | Leucine (L) |
| UUU | Phenylalanine (F) |
Note: The start codon, AUG, not only codes for the amino acid methionine (M) but also serves as the initiation signal for protein synthesis. Also, there are three stop codons (UAA, UAG, and UGA) that signal the termination of protein synthesis.
Keep in mind that this is a simplified version of the genetic code. There are also variations in the genetic code for certain organisms or specific organelles. However, the above table represents the standard genetic code used by most living organisms.
