Aim: How do scientists identify people using DNA Fingerprinting?

LO: SWBAT explain how scientists identify people using DNA fingerprinting DN: Why do we fingerprint people? What is it useful for? HW: read pp 322-325, page 339 #18-19 Fri: Review Book- Respiration Quarterly- Next Wed/Thurs

Why do we Fingerprint? So we can identify people

Why is DNA used to identify people? People have different DNA base sequences, therefore each individual will have a different DNA fingerprint.

Genetic Markers: ATTGCCTAGG - Individual 1 ATTGCCATGG - Individual 2 particular stretches of ____ that are _________ among individuals. DNA variable Our __________ regions are highly _________ from one individual to another and serve as good ________________ to be used for DNA fingerprinting. noncoding variable genetic markers

How do scientists make a DNA Fingerprint? Investigators need to find some ____ of the perpetrator. DNA Where can the investigators find the DNA? Blood Hair Nails Skin

Only a small amount of DNA is needed! Polymerase Chain Reaction: PCR The sample of DNA is amplified (___________) multiplied

PCR Animation

– + Gel Electrophoresis Amplified DNA is cut with specific __________________. 2) DNA segments are loaded into wells in a porous ____. 3) Electric current is passed through the gel making one side of the gel __ charged and one side __ charged. restriction enzymes gel – +

Gel Electrophoresis DNA is ___________ charged & moves through the gel to the _________ side. 5) Smaller segments move _______ & ________ than the larger segments. negatively positive faster farther

Gel Electrophoresis 6) The gel is then ________ so we can see the DNA ________ patterns. stained banding Result: The smaller segments of DNA are found closer to the _________ end than the larger segments. positive

**Separates DNA segments according to _____. SIZE

- + Gel Electrophoresis __ __ __ __ __ __ __ __ __ __ DNA Suspect A Suspect B Suspect C from CS __ __ __ __ __ __ __ __ __ __ +

DNA Fingerprint Questions: What is the charge of DNA? Where would we find the smallest DNA fragments, closer to the + end or the – end? Why do we get different banding patterns for each individual? 4) Which suspect was at the crime scene?