Q is for Glutamine, the most abundant amino acid in the body. In addition to protein synthesis, it is also used as an energy source for the immune system and is used as a substrate for synthesis of nucleotides. Normally, the human body can synthesize the necessary amount of Glutamine. However, under stress conditions, Glutamine must be supplied through food sources.
Glutamine is encoded by the codons CAA and CAG. Glutamine is often replaced by Histidine, which is encoded by nearby codons CAC and CAU. It is also often replaced by Glutamate, which is encoded by nearby codons GAA and GAG.
Notice how multiple universes are linked together. Mutations can occur at the nucleotide level and “nearby universes” will have single nucleotide mutations. These often result in the protein function also being similar, so that the actual real world impact of the molecular mutations is often very small in these “nearby universes”. The genetic code itself has evolved in the multiverse to be robust against mutation so that evolution through mutation and selection can occur. This robustness is likely present in all universes in which there is life on earth, as we know it.