For ten points, identify this technique involving in-vitro enzymatic amplification of DNA.
Precision mapping of CpG island methylation via this technique can be used to determine the state of an isolated chromatin sample. Exon and intron location is mapped using the RT-version of this, which includes a step using reverse transcriptase to generate a cDNA before the annealing step. The thermal denaturation step is eliminated in the helicase-dependent variety, and the extension step involves raising the temperature to ensure optimal Taq enzyme activity. The "tail" variant of this uses a nested pair of primers with different annealing temperatures, and non-specific background interference is reduced in its "touchdown" variety. For ten points, identify this technique involving in-vitro enzymatic amplification of DNA.
Precision mapping of CpG island methylation via this technique can be used to determine the state of an isolated chromatin sample.
{P}olymerase {C}hain {R}eaction