The characteristic of DNA that determines its migration rate during gel electrophoresis is the number of base pairs.
1. **Explanation**:
- DNA molecules have different lengths due to varying numbers of base pairs.
- Shorter DNA fragments containing fewer base pairs move faster through the gel compared to longer fragments during gel electrophoresis.
- This is because smaller DNA molecules can navigate more easily through the pores of the gel matrix, resulting in faster migration rates.
2. **Example**:
- If you have two DNA samples, one with 100 base pairs and the other with 200 base pairs, the sample with 100 base pairs will migrate quicker and farther in the gel compared to the 200 base pair sample.
Therefore, when analyzing DNA fragments using gel electrophoresis, the number of base pairs in the DNA fragment directly impacts its migration rate.
