Question

I would like to know how PCR helps in a Forensic Investigation.

Answer 1

Let's say a small trace of DNA is left at a crime scene. To see whether a certain allele is in it - an allele, say, which one of the suspects has but no one else does - the investigators would make a primer for that allele, use in PCR on their sample to see if the allele is indeed present in it (successful amplification = allele is present and suspect identified; no amplification = allele not present) or not.

Answer 2

check out chapter 19 - pp 529 and 560 of Becker's World of Cell, and Chapter 20 - pp 403-404, 417-420 of Campbell Biology 9th ed. The concepts and applications are covered in the DNA replication and Biotechnology

Answer 3

Becker's World of cell 8th edition