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:

•particular stretches of ____ that are _________ among individuals.

•Our __________ regions are highly _________ from one individual to another and serve as good ________________ to be used for DNA fingerprinting.

ATTGCCTAGG - Individual 1

ATTGCCATGG - Individual 2

DNAvariable

noncodingvariable

genetic markers

How do scientists make a DNA Fingerprint?

Investigators need to find some ____ of the

perpetrator.

Where can the investigators find the

DNA?1)Blood2)Hair 3)Nails4)Skin

DNA

Only a small amount of DNA is needed!

The sample of DNA is amplified (___________)

Polymerase Chain Reaction: PCR

multiplied

PCR Animation

Gel Electrophoresis1)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

4)DNA is ___________ charged & moves through the gel to the _________ side.

5) Smaller segments move _______ & ________ than the larger segments.

negativelypositive

fasterfarther

Gel Electrophoresis

Result: The smaller segments of DNA are found closer to the _________ end than the larger segments.

6) The gel is then ________ so we can see the DNA ________ patterns.

stainedbanding

positive

**Separates DNA

segments according to

_____.SIZE

Gel ElectrophoresisDNA Suspect A Suspect B Suspect C

from CS

__ __ __

__

__ __ __

__

__

__ __

__ __ __

__ __ __ __

-

+

DNA Fingerprint Questions:

1)What is the charge of DNA?2)Where would we find the smallest DNA

fragments, closer to the + end or the – end?

3)Why do we get different banding patterns for each individual?

4) Which suspect was at the crime scene?