Question

A section of DNA has the base sequence shown in #1. A mutation in this DNA strand results in the base sequence shown in #2. What type of mutation does this change represent?

#1 5' - AGCGTTACCGT-3'
#2 5'-AGGCGTTACCGT-3'

frameshift mutation
a missense mutation
a silent mutation
a point mutation

Answer 1

To determine the type of mutation represented by the change from sequence #1 to sequence #2, we can analyze the differences between the two sequences:

#1: 5' - AGCGTTACCGT - 3'
#2: 5' - AGGCGTTACCGT - 3'

The difference between the two sequences is the second base: 'C' in #1 has been changed to 'G' in #2.

This type of mutation where a single base pair is changed is known as a **point mutation**. Specifically, since the change results in one amino acid possibly being altered in the protein coded by this gene (if it affects a coding region), it could also be classified as a missense mutation if the new base leads to a different amino acid.

However, since the question asks for the type of mutation that occurred based on the base pair change alone, the most accurate answer is:

**a point mutation**.