How can we tell if the DNA in hair found at a crime scene came from the crime suspect? Since the DNA of every individual is unique, it should be possible to do genetic fingerprinting. It is too costly and time consuming to compare two DNA samples by looking at the sequence of bases (A,G,T and C) for all 3 billion nucleotide positions. Instead, restriction enzymes are used that cut the DNA whenever a certain sequence of bases occurs.

Copyright © The McGraw-Hill Companies, inc. Permission required for reproduction or display.