Question

Point mutation is __________

• A. change in gene
• B. change in one chromosome
• C. change in morphology of many chromosomes
• D. aneuploidy

Hint:

A point mutation changes a single base pair within a gene. Decide whether that is a change in gene or in chromosomes.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept
A point mutation is a change in a single base pair of DNA, by substitution, insertion or deletion of one base.

Step 2: Level of the change
Since the change lies inside one gene, it is a gene mutation. Sickle-cell anaemia, caused by a change from GAG to GUG in the beta globin gene, is an example.

Step 3: Compare the options
Change in chromosome number such as aneuploidy, or in chromosome structure, belongs to chromosomal aberrations and not to point mutations.

Final Answer:
A point mutation is a change in a gene. \[ \boxed{\text{(A) }\text{change in gene}} \]