Chapter 12, Problem 30P

A geneticist searching for mutations uses the restriction endonucleases $\text{SmaI}$ and $\text{PvuII}$ to search for mutations that eliminate restriction sites. $\text{SmaI}$ will not cleave DNA with CpGmethylation. It cleaves DNA at the restriction digestion sequence

$\text{5'-CCC GGG-3'}$

$\text{3'-GGG CCC-5'}$

$\text{PvuII}$ is not sensitive to CpG methylation. It cleaves DNA at the restriction sequence

$\text{5'-CAG CTG-3'}$

$\text{3'-GTC GAC-5'}$

a. What common feature do $\text{SmaI}$ and $\text{PvuII}$ share that would be useful to a researcher searching for mutations that disrupt restriction digestion?

b. What process is the researcher intending to detect with the use of these restriction enzymes?

c. Explain why CpG dinucleotides are hotspots of mutation.