Utopia or Dystopia
What is this?
DNA profiling (also called DNA testing, DNA typing, or genetic fingerprinting) is a technique that is used to assist in the identification of individuals by their respective DNA profiles. DNA profiles are encrypted sets of letters that reflect a person's DNA makeup, which can also be used as the person's identifier. DNA profiling should not be confused with full genome sequencing. DNA profiling is used in, for example, parental testing and criminal investigation. How does it work?
Although 99.9% of human DNA sequences are the same in every person, enough of the DNA is different that it is possible to distinguish one individual from another, unless they are monozygotic twins. DNA profiling uses repetitive sequences that are highly variable, called variable number tandem repeats (VNTRs), in particular short tandem repeats (STRs). VNTR loci are very similar between closely related humans, but are so variable that unrelated individuals are extremely unlikely to have the same VNTRs.
1) Sample of DNA obtained
2) Repetitive sequences of DNA used for profiling
3) produce more copies of DNA by polymerase chain reaction
4) cutting DNA into fragments using restriction enzymes (which are like chemical scissors) 5) separation into bands of DNA by electrophoresis
6) different pattern of bands with DNA from different individuals
- If bands are identical, the DNA came from the same person
- If they are similar, people are related
On the picture below, we can clearly see some similarities between child and Larry, so Larry, not Bob, is the father
Criminal investigations. Sometimes criminals leave something on the crime scene. It might be anything - saliva, semen, blood or any other fluid. If police can find and collect those, they can work out who committed the crime. Paternity tests. If a person is not sure, if it is his child, the paternity test can be done. It clearly shows...
References: Fiona Macrae. (2009). DNA evidence can be fabricated and planted at crime scenes. Available: http://www.dailymail.co.uk/sciencetech/article-1207389/DNA-evidence-fabricated-planted-crime-scenes-scientists-warn.html. Last accessed 2nd September 2014.
Shanna Freeman. (2008). How DNA Profiling Works. Available: http://science.howstuffworks.com/dna-profiling.htm. Last accessed 2nd of September 2014.
William Harris. (2009). How DNA Evidence works. Available: http://science.howstuffworks.com/life/genetic/dna-evidence8.htm. Last accessed 4th September 2014.
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