Genetic Fingerprinting.

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  • Created by: Molly
  • Created on: 28-04-14 11:20
What does genetic fingerprinting rely on?
The fact that the genome of any organism contains many repetitive, non-coding bases of DNA. 95% of human DNA does not code for any characteristics.
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What do introns contain?
Repetitive sequences of DNA called core sequences. For each individual, the length and number of core sequences is unique.
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What are the 5 stages of creating a genetic fingerprint?
Extraction, digestion, separation, hybridisation and development.
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What happens in extraction?
Tiny sample of animal tissue can produce a genetic fingerprint. The quantity of DNA can be increased using the polymerase chain reaction.
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What happens in digestion?
The DNA is cut into fragments using restriction endonucleases.
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What happens in separation?
The fragments of DNa are next separated according to size by gel electrophoresis.
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What is the gel immersed in and why?
Alkali, to separate the double strands into single strands.
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What is the process called where single strands are transferred to a nylon membrane?
Southern blotting.
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What are the stages of southern blotting?
Nylon membrane is laid over the gel. Membrane is covered with several sheets of absorbent paper which draws up liquid containing DNA through capillary action. This transfers the DNA to the nylon membrane in the same position as they are on the gel.
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How are DNA fragments fixed to the membrane?
Through the use of ultraviolet light.
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What happens in hybridisation?
Radioactive or fluorscent DNa probes are now used to bind with core sequences. The probes have base sequences that are complimentary to the core ones and bind to them under specific conditions e.g temp/pH. Each probe binds to a different core sequenc
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What happens in development?
An x-ray film is put over the nylon membrane. The film is exposed by the radiation from the probes. Because these probes correspond to position of DNA gragment, a series of bars is revealed. Pattern of bands is unique to each person except twins.
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How do you interpret the results of a genetic fingerprint?
If 2 different blood samples are found at a crime scene, it is matched against blood of a suspect. If there is a match, the pattern of bars is passed through a machine that calculates the length of the DNA fragments.
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List 3 uses of genetic fingerprinting?
Forensic science, indicating whether a person is connected to a crime or not. To identify paternity. Determining genetic variability within a population.
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Other cards in this set

Card 2

Front

What do introns contain?

Back

Repetitive sequences of DNA called core sequences. For each individual, the length and number of core sequences is unique.

Card 3

Front

What are the 5 stages of creating a genetic fingerprint?

Back

Preview of the front of card 3

Card 4

Front

What happens in extraction?

Back

Preview of the front of card 4

Card 5

Front

What happens in digestion?

Back

Preview of the front of card 5
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