Question

What is transition and transversion mutations respectively means?

• A. Purine is replaced by pyrimidine in transition and purine is replaced by purine in transversion
• B. Purine is replaced by purine in transition and purine is replaced by pyrimidine in transversion
• C. Purine is replaced by purine in transition and transversion
• D. Pyrimidine is replaced by pyrimidine in transition and in transversion

Hint:

• Transition Purine \(\leftrightarrow\) Purine (A \(\leftrightarrow\) G); Pyrimidine \(\leftrightarrow\) Pyrimidine (C \(\leftrightarrow\) T). (Same type of base).
• Transversion Purine \(\leftrightarrow\) Pyrimidine (A/G \(\leftrightarrow\) C/T). (Different type of base).
• Remember: PuR}ines are A}, G} (Pure As Gold). Pyrimidines are C}, T}, U} (CUT the Py).

Answer 1

The Correct Option is B

In the context of DNA mutations, the terms "transition" and "transversion" refer to specific types of point mutations that occur in the nucleotide sequence. To understand these mutations, it's essential to recall that DNA is composed of four types of nucleobases, which are categorized into purines and pyrimidines:

• Purines: Adenine (A) and Guanine (G)
• Pyrimidines: Cytosine (C) and Thymine (T)

With this in mind, let's define each type of mutation:

1. Transition Mutation:

This occurs when a purine is replaced by another purine (A ↔ G) or when a pyrimidine is replaced by another pyrimidine (C ↔ T). Transitions are more common than transversions.

1. Transversion Mutation:

This occurs when a purine is replaced by a pyrimidine (A or G ↔ C or T) or vice versa. These changes result in more significant structural changes in the DNA.

Hence, the correct interpretation of transition and transversion mutations is:

Purine is replaced by purine in transition and purine is replaced by pyrimidine in transversion.