aim: how do scientists identify people using dna fingerprinting?
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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?
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