Question

What are the clinical implications of

a. Point mutations

b. Frame shift mutations

Answer 1

Ans) a) Point mutations:

- A mutation affecting only one or very few nucleotides in a gene sequence.

The protein may lose its function, which can result in a disease in the organism. For example, sickle-cell disease is caused by a single point mutation (a missense mutation) in the beta-hemoglobin gene that converts a GAG codon into GUG, which encodes the amino acid valine rather than glutamic acid.

b) Frame shift mutations:

- Additions or deletions of a nucleotide that cause a shift in the grouping of codons.

- Frameshift mutations are the most devastating because they change the entire reading frame of the mRNA and every amino acid is different from what was originally coded for in the DNA.

- Severe genetic diseases such as Tay–Sachs disease; they increase susceptibility to certain cancers and classes of familial hypercholesterolaemia; in 1997, a frameshift mutation was linked to resistance to infection by the HIV retrovirus.