GCSE Biology Question Analysis Topic: Biology - DNA
Exam Question:
A burglar in a huff forgot to wipe off his blood stains from the place of crime where he was involved in a theft. Name the technique which can help in identifying the burglar from the blood stains. Describe the technique.
Answer:
For GCSE Biology, you should know:
A forensic method known as DNA fingerprinting uses DNA features to identify people. The idea behind DNA fingerprinting is that, like fingerprints, no two people have exactly the same nucleotide sequence. The extraction of usable DNA is the first stage in the DNA fingerprinting process. The usable DNA is then digested with restriction enzymes to yield restriction fragments length polymorphisms, or RFLPs, which are subsequently sorted by size using gel electrophoresis.
The sorted DNA fragments are subsequently transferred by southern blotting from the gel to the surface of the nylon. In order to match different DNA samples, radioactive probes are then washed over the nylon surface to enable their connecting to any DNA fragments of the identical composition.
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