Wobble Hypothesis - The genetic code is a degenerate code, meaning that a given amino acid may have more than one codon.

Therefore for these eight amino acids, the codon need only be read in the first two positions because the same amino acid will be represented regardless of the third base of the codon.

These eight groups of codons are termed unmixed families of codons. An unmixed family is the four codons beginning with the same two bases that specify single amino acids. For example, the codon family GUX codes for valine.