Palaeontologists unearthed a human skull during excavation. A small fragment of scalp tissue was still attached to it. Only little DNA could be extracted from it. If the genes of the ancient man need to be analysed, the best way of getting sufficient amount of DNA from this extract is:
The Polymerase Chain reaction (PCR) is a technique by which small samples of DNA can be quickly amplified. Starting with only one gene sized piece of DNA, this technique is used to make literally billion copies in only a few hours.