DNA Fingerprinting/profiling
A quick mindmap to show DNA profiling/fingerprinting via PCR and gel electrophoresis
- Created by: Rebekah Allanah
- Created on: 08-05-14 12:45
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- DNA Fingerprinting
- PCR
- Reactants: DNA samples, DNA polymerase,the four nucleotide bases and primers
- The reactants are placed in a vial
- The mixture is heated to 90-95'C
- This is done to separate the two DNA strands as the hydrogen bonds break down
- The mixture is cooled to 50-60'C
- This causes the primers to bind (anneal) to the single DNA strands
- The mixture is reheated to 75'C - the optimum temperature for the enzyme to build the complimentary strands of DNA
- Gel Electrophesis
- The DNA fragments are each put in their own well of the agarose gel
- The agarose gel is completely covered with a buffer
- an electrical current is passed through the apparatus and the DNA fragments move towards the negative anode
- One the process is complete the gel is left in a dye and the dye is the rinsed off
- This process dyes the DNA fragments, it become even clearer if the gel block is placed on a light box
- Prep
- DNA extracted from sample
- The DNA is split into fragments using restriction enzymes
- differenty restriction enzymes cut at different recognition points
- Southern blotting
- An alkaline buffer solution is added to the gel after electrophoresis
- A nylon filter is placed over it
- Dry, absorbent paper is used to draw the solution containing the fragments from the gel to the filter leaving 'blots'
- The alkaline solution also denatures the fragments so the strands separate and the base sequences are exposed
- Dry, absorbent paper is used to draw the solution containing the fragments from the gel to the filter leaving 'blots'
- A nylon filter is placed over it
- An alkaline buffer solution is added to the gel after electrophoresis
- DNA
- Introns are sections of non-coding DNA that are unique to each person, therefore can be used in DNA profiling
- Mini-satellites
- 20-50 long base sequence repeated from 50 to several hundred times
- Micro-satellites
- 2-4 bases long sequence that is repeated between 5 and 15 times
- The more closely related two individuals are, the more similar the DNA patterns are
- PCR
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