B8 human biochem (ijat)

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B8 human biochem (ijat)

  1. 1. DNA PROFILING IS USED TO IDENTIFY AN INDIVIDUAL A process where we used to analysis our DNA. For example; through traces left by our fingerprints.
  2. 2. THE PROCEDUREFirst, The DNA to be identified is extracted from the source (blood stain or any sample taken from the subject). The DNA is cut into small pieces using restriction enzymes. This is because the easiest place to detect the unique nature of individual DNA is in regions where short sequences of bases are repeated variable number of times-short tandem repeats (STRs)
  3. 3. Second, Polymerase chain reaction (PCR) technique is used to amplify these regions in the DNA by making multiple copies. It use: i) sequence-specific primer to bind to the DNA that has been separated into single strands. ii) a heat-stable version of the enzyme DNA polymerase to polymerized these sections. Temperature : 70˚C This process can add up to a thousand bases per minute.
  4. 4. Third, The DNA fragments are then separated and detected using gel electrophoresis. Due to its phosphate groups, DNA carries a negative charge. So, the fragments move towards the positive terminal by a distance that corresponds to their molecular sizesshorter fragments move further than longer fragments. The nitrocellulose sheet used in the electrophoresis is treated with radiation. This produces an Autoradiogram  showing the position of the fragments as dark bands.
  5. 5. Applications of DNA ProfilingTo identify victims.In forensic cases, to identify the suspect.To confirm biological relationships betweenindividuals.To determine relationships betweenpopulations in the study of evolution,migration and ecology.

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