Which of the following sequences is an example of a point mutation of the DNA sequence -A-A-G-T-G-C- ? (What?)
-A-A-A-T-G-C-
-A-A-G-U-G-C-
-G-T-A-G-A-A-C-
-A-A-G-G-T-C-
A point mutation is a a mutation affecting only one or very few nucleotides in a gene sequence. So out of those four choices, it would be where only one is affected. The first choice, (A-A-A-T-G-C) Is correct.
To identify a point mutation in the DNA sequence -A-A-G-T-G-C-, we need to compare it with the given sequences and look for any changes in individual nucleotides. A point mutation occurs when a single nucleotide is swapped, deleted, or inserted into the DNA sequence.
Let's analyze each of the given sequences:
1. -A-A-A-T-G-C-: This sequence has a point mutation where the third nucleotide 'G' is changed to 'A'. Therefore, this sequence is an example of a point mutation.
2. -A-A-G-U-G-C-: In DNA, the nucleotide 'U' does not exist, and it is typically found in RNA. Therefore, this sequence does not represent a valid DNA sequence.
3. -G-T-A-G-A-A-C-: This sequence does not have a point mutation as it is entirely different from the original DNA sequence.
4. -A-A-G-G-T-C-: This sequence has a point mutation where the fourth nucleotide 'T' is changed to 'G'. Therefore, this sequence is an example of a point mutation.
So, the correct answer is the sequence -A-A-A-T-G-C-, as it represents a point mutation by changing the third nucleotide from 'G' to 'A' in the original DNA sequence.