miniPCR bio
TM
Chopped! Using CRISPR/Cas9 to cut DNA - Student's Guide
Version: 1.0 - Release: May 2022 - © 2022 by miniPCR bio™
Student's Guide
P./37
Advanced discussion
In Tubes C and D, cutting was likely not 100% complete as evidenced by the presence of a band of
the same size as the uncut DNA from Tube A. For reasons that aren't always clear, different gRNAs
can target DNA with higher or lower efficiency.
1. When performing gel electrophoresis, you can determine which bands have more DNA
based on their relative brightness; when comparing two bands of the same size, the brighter
band has more DNA. (You may wish to consult with other lab groups in order to evaluate
more data.)
a. Compare your results from Tube C versus Tube D. Which one had the brighter band of
uncut DNA?
b. What does this suggest about the efficiency of the two gRNAs used in this experiment?
Explain your answer.
2. Scientists often have to test multiple gRNAs to find the most efficient one for their
experiment. Comparing the two gRNAs you have tested, if you had to advise a scientist
which gRNA was better for cutting this sample of DNA, which one would you choose? Justify
your answer.
