3.8.4.3 Genetic Fingerprinting Flashcards
What is the difference between a DNA probe or a primer?
DNA probe: identifiable label, used in DNA hybridisation, stand alone unit
Primer: no label, occurs in in vitro gene cloning
What is the purpose of gel electrophoresis?
It seperates DNA fragments of different lengths
This confirms the presence of a mutation / probe has annealed to the DNA / probe has annealed to the desired locus
What is the process of gel electrophoresis?
Completely submerged in pH buffer
Wells have to face the negative electrode
Gel is at the bottom of the wells
DNA sample goes into the wells
DNA is slightly negatively charged so DNA will move away from the negative electrode
Larger DNA fragments will move slowly through the gel which separates the DNA based on lengths
DNA moves through the gel, not on top of it
A DNA ladder, created by gel electrophoresis contains known sizes of fragments that are all labelled with a marker
What is genetic fingerprinting?
The use of gel electrophoresis to identify a person
How does PCR help gel electrophoresis?
It amplifies the sample so more electrophoresis can be undertaken
What does each line correlate to in gel electrophoresis?
A DNA fragment
What are introns called in genetic engineering?
Mini satelites
Variable number tandem repeats (VNTRs)
What type of DNA is VNTRs?
Non-coding
Are VNTRs inherited?
Yes, in exactly the same way that coding DNA is inherited
What needs to occur in genetic fingerprinting specifically?
All fragments must be marked
What needs to happen to the DNA fragments before being added to the wells for gel electrophoresis?
Stain the solution
This allows it to sink into the well so that it moves through the gel, not on top of it
It also allows you to see the fragments moving through the gel
It doesn’t stain the DNA but it is carried through the solution by the DNA molecules
What recepticle is gel electrophoresis completed in?
A gel electrophoresis tank
