DNA Fingerprinting | Genetics – DNA profiling, DNA fingerprinting is the process that is used to identify a individual from a DNA sample by observing specific patterns in their DNA.
What is DNA fingerprinting or DNA profiling?
Leicester Geneticist University Sir Alec Jeffrey’s invention of a methodology known as DNA fingerprints allows matching DNA samples from different individuals for similarities and variations.
In the resolution of crimes that it is used to detect and can even determine how people are related to one another through paternity tests of two people in the world have 99.9% of their DNA the same so this process analyzes the differences in the remaining 0.1% this modern technology is called DNA profiling.
There are sections or loci of the chromosome, which instead of a gene consisting of a long sequence of bases there are significantly shorter sequences of three or five bases, which often repeated these sequences is called short tandem repeats, or STRs. This technique is a very sensitive one that requires only a few skin cells of hair root or a small amount of blood or saliva.
There are areas that vary in number of repeats DNA profiling only looks at these STRs, a cell sample is collected this could be from some blood at a crime scene or a swab from the inside of someone’s cheek for example.
The DNA is then extracted from the sample many copies of this DNA may be made using the polymerase chain reaction or PCR special enzymes called restriction endonuclease are used to cut the DNA up into different sized pieces the DNA samples are then put into wells in a special gel called agarose for the process of gel electrophoresis.
This separates the DNA fragments by size the pattern is then transferred to a nylon sheet in southern blotting and finally the lines produced by the DNA samples from different people are compared.
These are often used as DNA profiles to solve some mysteries an item was stolen in a burglary, a drop of blood was left behind by the thief. Samples of DNA are taken from the suspects and compared to the sample left at the crime scene to find which suspect is guilty.
Modern-day DNA profiling is also known as an STR analysis, based on microsatellites rather than fingerprinting minisatellites.
The smaller minisatellite parents normally are two to five base pairs long, or short tandem repeaters (STRs). Like miniature satellites the whole human genome, for instance, ‘TATATATATATA’ is repeated many times.
How are DNA profiles stored?
DNA profiles are usually stored in government databases to avoid misuse and security breach.
The United Kingdom became the first country in 1995 to create a national DNA profile database.
A select number of UK persons, most of whom are linked to severe crimes, are identified on the UK National DNA Database.
The Security of Freedom Act 2013 enshrined the removal from the UK National DNA Database of 1,766,000 DNA profiles from innocent children and adults.
The national DNA database is now in most countries.
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