What is DNA and DNA Fingerprinting?
DNA, also known as deoxyribonucleic acid, is a material that carries all the information about how a living thing will function and look. It's passed on from parents to their children and is found in every cell. Your DNA is specific only to you. With identical twins, they may have the same genetic code, but they do not share 100% of their DNA or have the same fingerprint. DNA fingerprinting is a laboratory technique used in forensic science. It helps find a link between evidence from a crime scene and a suspect in a criminal investigation. It involves identifying someone by looking at the unique patterns in their DNA.
How was DNA Fingerprinting Created and how is it Done?
The technique for DNA fingerprinting was created by Alec Jefferys in 1984. He noticed that certain sequences of DNA are repeated within genes. He saw that each individual has a unique pattern of these sequences. Modern day DNA profiling is also called STR analysis. It is incredibly sensitive so it only needs a small amount of someone’s DNA to produce a reliable result. DNA can be extracted from blood, saliva and hair. At the crime scene, a DNA sample is taken. It is later compared with a suspect's DNA. If the two samples match, then the evidence came from that suspect. If the samples do not match, then the evidence did not come from the suspect.
How is DNA Fingerprinting used?
DNA fingerprinting is used in legal disputes and to establish paternity. You get half your DNA from your mother and half from your father. DNA profiling can confirm whether two people are related to each other. It has led to the conviction of many criminals and the freeing of many of those who were wrongly convicted. Scientific identification technology is sometimes problematic; a suggestion of the possibility of a mistake in the science can be enough to convince a jury not to convict a suspect. Instances such as sample contamination, faulty preparation procedures, and mistakes in interpretation of results are major sources of error but DNA fingerprinting has a high success rate and few false-positives.
How are DNA Profiles Stored?
In 1995, the UK was the first country to set up a national database of DNA profiles. It holds the DNA profiles from a select number of individuals; most of them are linked to very serious crimes. Most countries have a national DNA database.
Written by: Maysa Nashawati
References:
“DNA Fingerprinting.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., www.britannica.com/science/DNA-fingerprinting.
“DNA Fingerprinting.” Genome.gov, www.genome.gov/genetics-glossary/DNA-Fingerprinting.
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