Question

Most nonsense mutations in genes that encode structural proteins cause a null ("knockout") phenotype.

How many "sense" codons can be converted into nonsense codons (TAA, TAG, TGA) by single base pair substitution mutations?

Answer 1

2. TGA (opal)

Explained below

Step-by-step explanation:

A mutation in a gene that results in total loss of the normal function of the gene product encoded by that gene, resulting in a Null phenotype.

Changes in DNA sequence are termed as nonsense mutation that introduce a stop codon, resulting in a non functional protein. This terminology results stop codons have also worked as nonsense codons.

There are three different stop codon-

In RNA

1. UAG (amber)
2. UAA (ochre)
3. UGA (opal)

In DNA

1. TAG (amber)
2. TAA (ochre)
3. TGA (opal)