Genetic Fingerprinting

Question 1

What is Genetic Fingerprinting?

Answer 1

> The examination of VNTRs

> VNTRs are found in the introns ( non-coding regions ) of mRNA

> The more closely related you are, the more similar your VNTRs are

Question 2

Genetic Fingerprinting:
Collection

Answer 2

> DNA sample collected e.g. blood, hair

> PCR used to amplify small amounts of

Question 3

Genetic Fingerprinting: Digestion

Answer 3

> Restricion endonucleases cut the DNA into smaller fragments

> They are chosen to be complementary to the sequence before & after the VNTR so it is not cut

Question 4

Genetic Fingerprinting: Separation

Answer 4

> Samples put in wells in agar gel

> Placed in a buffer liquid with an electrical voltage

> DNA is negatively charged, so samples will move through the agar to the positive side of the gel

> Smaller samples move faster and further ( this is how different VNTR lengths are separated )

> An alkaline is added to separate them into single strands

Question 5

Genetic Fingerprinting: Hybridisation

Answer 5

> DNA probes added which are either radioactively / fluorescently labelled

> DNA probes bind to DNA VNTRs

Question 6

Genetic Fingerprinting: Development

Answer 6

> Transfer DNA VNTRs with DNA probes onto a nylon sheet

> X-ray or UV light to visualise probes

Question 7

Genetic Fingerprinting: Analysis

Answer 7

> Position of the DNA bands are compared for identification