There was a time when to amplify DNA,
You had to grow tons and tons of tiny cells.
Then along came a guy named Dr. Kary Mullis,
Said you can amplify in vitro just as well.
Just mix your template with a buffer and some primers,
Nucleotides and polymerases, too.
Denaturing, annealing, and extending.
Well it’s amazing what heating and cooling and heating will do.
PCR, when you need to detect mutations.
PCR, when you need to recombine.
PCR, when you need to find out who the daddy is.
PCR, when you need to solve a crime.