Question

Degenerate codons as you mentioned can code the same amino acid. You claimed it as one gene coding for different polypeptides. Would the nucleotide sequence change still be accounted as a single gene?

Answer 1

Yes

DNA is a dynamic molecule.The nucleotide sequence found within it are subjected to change as the result of phenomenon called mutation.

With a base substitution mutation,only a single nucleotide within a gene sequence is changed,only one codon is affected.For example,during replication, a thymine nucleotide might be inserted in place of a guanine nucleotide.Although a base substitution alters only a single codon in a gene ,having significant impact on protien production.