Question

Differentiate between transition and transversion.

Give one significant difference between the following:

Transition and transversion

Answer 1

Aspect	Transition	Transversion
Definition	Transition mutations are base pair replacements where a purine is replaced by another purine or a pyrimidine is replaced by another pyrimidine.	Transversion mutations are base pair replacements where a purine is replaced by a pyrimidine or a pyrimidine is replaced by a purine.
Base Pair Example	For example, an AT base pair can be replaced by a GC base pair and vice-versa.	For example, a CG base pair can be replaced by GC, or AT can be replaced by TA.
Molecular Nature	Substitution within the same type of nitrogenous base (purine to purine or pyrimidine to pyrimidine).	Substitution between different types of nitrogenous bases (purine to pyrimidine or pyrimidine to purine).
Cause	Occur due to mistakes in the incorporation of nucleic acid precursors or during DNA replication.	Also occur due to mistakes in the incorporation of nucleic acid precursors or during DNA replication.

Answer 2

Transition	Transversion
In transition mutations, a purine base (adenine [A] or guanine [G]) is replaced with another purine base, or a pyrimidine base (cytosine [C] or thymine [T]) is replaced with another pyrimidine base.	In transversion mutations, a purine base is replaced with a pyrimidine base, or a pyrimidine base is replaced with a purine base. Examples: Adenine (A) replaced with Cytosine (C) or Thymine (T), or Guanine (G) replaced with Cytosine (C) or Thymine (T), and vice versa.