Question

Transition type of gene mutation is caused when
(A) GC is replaced by TA
(B) CG is replaced by GC
(C) AT is replaced by CG
(D) AT is replaced by GC

Answer 1

Hint: Gene mutation is the alteration in the NDA sequence that makes up the genetic material permanently. It can occur even in the DNA base pair or even in the whole chromosome that is with the multiple gene. This is inherited from the one generation to the other generation.

Complete answer:
The mutation in the gene is classified into three types as the insertion, deletion or the substitution gene mutation. In the insertion, the base pair is added to the nucleotide sequence. In the deletion, the base pair is deleted or removed from the nucleotide sequence of the gene. In the substitution mutation, the one base pair gets substituted with the other. In this type of mutation, point mutation is the most commonly occurred.

This point mutation is again divided into transition and the transversion mutation. Transition point mutation occurs when the one purine base pair substituted with the other purine or the one pyrimidine base pair substituted with the other pyrimidine. Hence the adenine thymine is replaced by the guanine cytokine is the transition mutation.

Hence the correct answer is OPTION(D)

Note: The purine consists of the six nitrogenous molecules like adenine, guanine, hypoxanthine and the xanthine. The pyrimidines structure consists of the thymine, cytosine, uracil and the orotic acid. Adenine, guanine and the cytosine are found in both DNA and RNA.