C rime S cene I nvestigation

Who Ate The Cheese? Oh no! Someone ate the Queen ’ s prize Limburger cheese! Saliva samples were taken from the teeth marks left on the cheese How can we determine who ate the cheese?

DNA Fingerprinting A process which uses fragments of DNA to identify the unique genetic makeup of an individual. 1.PCR 2.Restriction Enzymes 3.Electrophoresis

PCR Polymerase Chain Reaction –Replicates DNA sample –Produces millions of copies in 2 hours

Restriction Enzymes Molecules that cut DNA segments into smaller pieces by breaking bonds Cuts DNA into fragments of different lengths

Gel Electrophoresis GEL ELECTROPHORESIS –DNA molecules have a negative charge. –The molecules migrate toward the positive pole. –The larger the molecule, the more difficult it is to make its way through the gel, so the shorter segments move farther than longer ones.

DGGE Denaturing gradient gel electrophoresis DNA melts! Temperature of melting point determined by G/C content Can separate DNA by melting point = different genes

Who ate the cheese? Today you are going to solve a crime using the techniques you just learned!

Crime Scene Photo