DNA Profiling

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DNA profiling is the use of genetic material, usually nuclear DNA or mitochondrial DNA, to establish who the donor of the sample is. It is also the use of this genetic material to establish genetic connections, usually paternity or kinship.
The method that is usually used to obtain the results is electrophoresis.
There are three groups of genetic material used for these tests, they are:
  • Minisatellites- typically 20-100 base pair lengths that are repeated consecutively up to 100 times.
  • Microsatellites- a smaller version of minisatelites, usually 2-8 base pair lengths that repeat 2-20 times.
  • SNPs- variation in the individual base at a certain part of the genome and use single base pairs

DNA analysis also establishes the origin of a biological sample to a high degree of probability, which is one reason why it is more readily accepted into a court of law than most forensic results.
The types of biological materials that can be tested include:
  • blood
  • semen
  • hair (usually root of hair is needed also)
  • saliva
  • vaginal fluids

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Picture Source: http://www.forensicscience.ie/index.asp?locID=18&docID=-1