E X E R C I S E S
I. Interpreting Your Gel
1. Observe the photograph of the stained gel containing your sample and those from other students. Orient the photograph with the sample wells at the top. Interpret the band(s) in each lane of the gel:
2. How would you interpret a lane in which you observe primer dimer, but no 440-bp band?
3. The mt control region mutates at approximately 10 times the rate of nuclear DNA. Propose a biological reason for the high mutation rate of mt DNA.
4. The high mutability of the mt genome means that it evolves more quickly than the nuclear genome. This makes the mt control region a laboratory for the study of DNA evolution. However, can you think of any drawbacks to this high mutation rate?
5. There are numerous insertions of mt DNA into nuclear chromosomes. Notably, scientists recently discovered a 540-bp fragment of the mt control region that inserted into chromosome 11 approximately 350,000 years ago. Would you expect any difference in the mutation rates of the control region sequence in the mt genome versus the chromosome 11 insertion? What implication does this have in the study of human evolution?
M I T O C H ON D R I A L C O N T R O L R E G I O N
DNA Learning Center, Cold Spring Harbor Laboratory
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