Process of Genetic Profiling (WJEC GCSE Biology: Combined Science)

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Process of Genetic Profiling

  • Genetic profiling (DNA profiling) enables scientists to identify individuals based on their unique DNA 
  • Every person (apart from identical twins) has a DNA profile which is unique to them
    • The more closely related you are to a person the more similar your genetic profiles are
  • To create a DNA profile from a sample of DNA, scientists complete the following in sequence:
    • Obtain the DNA, which can be extracted from the root of a hair, a spot of blood or semen or saliva
    • Use enzymes to cut the DNA into fragments of different sizes
      • The sizes of the fragments are different for each person due to the unique nature of DNA
    • Separate the fragments using gel electrophoresis
      • DNA is suspended in an alkaline (agarose) gel
      • An electrical current is run through the gel
      • DNA is negatively charged and so moves toward the positive end of the gel 
      • Smaller fragments travel faster than larger fragments
    • The profile is then treated so that the fragments of DNA can be seen in bars (the DNA profile)
    • The pattern of the DNA profile is then analysed

The process of genetic profiling diagram

The equipment required to create a genetic profile

Gel electrophoresis is used to create genetic profiles by separating the fragments of DNA from a sample

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Ruth

Author: Ruth

Ruth graduated from Sheffield University with a degree in Biology and went on to teach Science in London whilst also completing an MA in innovation in Education. With 10 years of teaching experience across the 3 key science disciplines, Ruth decided to set up a tutoring business to support students in her local area. Ruth has worked with several exam boards and loves to use her experience to produce educational materials which make the mark schemes accessible to all students.