Question

Which of the given disorders can be seen in an individual, when the mutation includes the substitution of a purine by pyrimidine?

• A. Transversion
• B. Transition
• C. Tautomerisation
• D. Frameshift mutation

Answer 1

The correct option is A

Transversion

The correct option is A.

Explanation for the correct option:

1. In molecular biology, a point mutation occurs when a single (two ring) purine (A or G) is replaced by a (one ring) pyrimidine (T or C), or vice versa. Ionizing radiation or alkylating chemicals can trigger a transversion, which can be spontaneous or induced by ionizing radiation.
2. A transversion mutation can cause sickle cell anemia.
3. A transversion mutation occurs when pyrimidine substitutes purine in a point mutation.

Explanation for the incorrect options

Option B:

A transition is a point mutation in genetics and molecular biology that converts a purine nucleotide to another purine (A G) or a pyrimidine nucleotide to another pyrimidine (C T). Transitions account for about two out of every three single nucleotide polymorphisms (SNPs).

Option C:

1. Tautomers are several types of bases that are created by rearranging electrons and protons in molecules.
2. Certain chemical mutagens produce tautomerism. Purines pair with pyrimidines in the following replication, and the base pair at a specific locus is changed.

Option D:

1. A frameshift mutation is a genetic mutation that occurs when a loss or insertion in a DNA sequence causes the sequence to be read in a different way.
2. A DNA sequence is made up of a series of smaller molecules known as nucleotides.

Final answer: The mutation includes the substitution of a purine by a pyrimidine and is termed a Transversion.