Index >> Gene Mutation >> Mutation in Termination Codons

Mutation in Termination Codons -

Mutations which are the reverse of nonsense mutations also occur. Thus a mutation can convert a termination codon to a sense codon specifying some amino acid.

The α chain of human haelogmobin is normally 141 amino acid residues long. A mutation (U-->C) converts the termination codon UAA to CAA, the codon for glutamine.

Chain synthesis therefore proceeds beyond the normal termination point, producing a polypeptide chain containing 172 amino acids.