In DNA printing, genetic code becomes computer code. This transformation occurs when the chemical bases adenine, thymine, cytosine and guanine present in a chemical mix or gene sequence are translated by computer through gel electrophoresis technology into their representative letters: A/T, T/A, C/G, G/C. This alphabet code was formalized in 1970 by the International Union of Pure and Applied Chemistry for integration into a text-based bioinformatics format, called "FASTA," in which nucleotides are represented symbolically using single letters.