Question

There is only one possible sequence of amino acids when deduced from a given nucleotides. But multiple nucleotides sequence can be deduced from a single amino acid sequence. Explain this phenomena.

Answer 1

Some amino acids are coded by more then one codon (known as degeneracy of codons), hence, on deducing a nucleotide sequence from an amino acid sequence, multiple nucleotide sequence will be obtained, e.g.e, lle (Isoleucine) has three codons AUU, AUG, AUA. Hence, a dipeptde met-lle can have the folloing nucleotide sequence.
(i) AUG-AUU
(ii) AUG-AUC
(iii) AUG-AUA
And if , we deduce amion acid sequence from the above nucleotide sequences. all the three will code for Met-lle