Question

Two blood samples A and B were picked up from a crime scene. How would you determine if the samples belong to the same individual or different individuals? Explain your result. [5]

Answer 1

It can be determined by DNA fingerprinting technique [1]. It involves the following processes: [0.5 mark for each point]
(i) isolation of DNA from the sample
(ii) digestion of DNA by restriction endonuclease
(iii) separation of DNA fragments by electrophoresis
(iv) transferring (blotting) of separated DNA fragments to synthetic membranes, such as nitrocellulose or nylon
(v) hybridisation using labelled VNTR probe
(vi) detection of hybridised DNA fragments by autoradiography

If the banding pattern of DNA in the autoradiograph from samples A and B are matched, then sample A and B would be from same individual. If the banding pattern of DNA in the autoradiograph from samples A and B are different, then samples A and B are from different individual. [1]