Page 9 - An Identity Crisis

Pre-Lab

Solutions

DNA Background Procedure

1. What is the key difference 6. How much DNA goes into each lane?
between PCR and RFLP? 10 μL.
Instead of cutting out the needed portions of
DNA from a large sample, PCR amplifies the
portions of interest from a much smaller sample. 7. What always goes in the first lane of the gel?
The ladder

2. Why does this difference make PCR better
suited for forensics? 8. Why is it important to write down the loading
PCR requires less DNA for analysis. order of the samples in the wells?
If a record is kept of the loading order, then the
data is still usable even if you accidentally deviate
3. What causes DNA to move during from the order set in the procedure.
electrophoresis?
DNA is negatively charged and is attracted to the
positive pole when subjected to an electric field. 9. Which direction does DNA travel? Should
the wells be on the end near the black or red
electrode?
4. How is the DNA sorted after electrophoresis? DNA travels to the positive pole. It should be on
DNA is sorted with the largest bands nearest to the end with the black electrodes.
the wells and the smallest bands farthest away.

5. What is a ladder?
A ladder contains pieces of DNA of a known
length for comparison to unknown DNA
samples run on the gel.

THE MYSTERY OF LYLE AND LOUISE 9