The occurrence of nonstandard base pairing between the anticodon of certain transfer RNA (tRNA) molecules and codons of messenger RNA (mRNA) during translation of the genetic message that directs protein synthesis in living cells. The bases in positions 3 and 2 of the anticodon (corresponding to positions 1 and 2 of the codon) observe strictly standard pairing, whereas the base in position 1 of the anticodon can ‘wobble’ somewhat in its pairing. Hence, the cell does not need a unique tRNA for each of the 61 codons that encode amino acids, but requires only about 40 or so tRNAs, to ensure that each codon binds to a tRNA carrying the correct amino acid. See genetic code.