Question

Which type of mutation is being shown by new DNA sequence?

Original DNA sequence: CAGCT-CCG

New DNA sequence: CTAGCTACCC

I. Point mutation

II. Deletion

III. Frameshift

• A. I only
• B. II only
• C. III only
• D. I and II
• E. I and III

Answer 1

Answer: (C)

III only

Loss of one or more nucleotide bases to the DNA segment by removal of an intercalary DNA segment is known as deletion. Since the new DNA sequence has additional nucleotides, the deletion has not taken place. Loss of one or more nucleotide bases to the DNA segment by removal of an intercalary DNA segment is known as deletion. Change in one nucleotide in a gene or DNA sequence is referred to as gene mutations or point mutations. Since the new DNA sequence has additional two bases, it is not point mutation. Insertion or deletion of nucleotides, not divisible by three, refers to as frameshift mutation. In the given question, there is an addition of two bases which has changed in reading frame completely. Hence, it is showing frame shift mutation.

Therefore, the correct answer is option C.