A substitution mutation occurs when one base in the DNA sequence is replaced with another.
Let's analyze the options based on the given original DNA sequence:
Original Sequence:
C G T T A C T G C A A T
G C A A T G A C G T T A
a.
C G T C T A C T G C A A T
G C A G A T G A C G T T A
- The first row has a substitution at the second position (T changed to C) and at the last position (A changed to G).
- The second row has a substitution at the third position (A changed to G).
b.
C G T G A C T G C A A T
G C A C T G A C G T T A
- The first row has a substitution at the third position (T changed to G).
- The second row has a substitution at the second position (A changed to C).
c.
C G T T A C T G C A A T
G C A A T G A C G T T A
- This option is exactly the same as the original sequence, meaning no mutation has occurred.
d.
C G T A C T G C A A T
G C A T G A C G T T A
- The first row has a substitution at the third position (T changed to A).
- The second row has a substitution at the third position (A changed to T).
Based on this analysis, the sequences with substitution mutations are options a, b, and d.
If we are looking for just one option that shows a substitution mutation, any of these (a, b, or d) would qualify. However, since only one answer is needed, and based on the options listed:
d. C G T A C T G C A A T
G C A T G A C G T T A
This option clearly shows substitutions that can be easily observed in both rows.
Correct answer: d.
1 answer