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DNA FINGER PRINTING
Information about DNA finger printing
Unlike a conventional fingerprint that occurs only on the fingertips and can be altered by surgery, a DNA fingerprint is the same for every tissue , and organ of a person . It cannot be altered by any known treatment .
Fingerprinting with ink and paper , based on fingertip ridge patterns is the standard method for personal identification. Finger prints are constant throughout life, finger prints can be used to distinguish one person from any other. Similarly the DNA of every individual is also unique in its own way. Actually the method should be called simply DNA printing or DNA typing since it has nothing to do with the fingers. The degree of variation in bands from one person to another is so large that the theoretical probability that the bands seen in one individual are present in another unrelated individual may be in millions. The advantages over finger prints are numerous. DNA can be isolated from any part of the body, skin cells, blood or blood stains or semen.
The human DNA is different from other living organisms Hence blood of an animal will have different DNA sequence and characteristics. Hence DNA fingerprinting is a very quick way to compare the DNA sequences of any two living organisms.
However some of the disadvantages of DNA finger printing are:
1. It requires further standardization and quality control, to be universally accepted as a tool.
2. There are only a few reliable labs around the world that can give accurate results
3. There is also 1 in 50 billion chance of two DNA sequence being similar
APPLICATION OF DNA FINGER PRINTING
1. It is currently employed in paternity disputes
2. Identification of bodies of soldiers killed in war. It was also used for identification of the body of Nazi physician Joseph Mengele, the so-called "Angel of Death." In fact it has been used a to reunite a kid lost in the Tsunami with his parents.
3. To diagnose inherited disorders in both prenatal and newborn babies, like -
a. Cystic fibrosis
b. Sickle cell anemia
c.Thalassemia
d. Hemophilia
e. Huntington's disease
f. Alzheimer's Disease( Familial Type)
g. Huntington's Chorea
h. Marfan's syndrome
Many other similar disorders can be diagnosed
4. Biological Evidence to identify criminals: Where fingerprints are not available but biological specimens are available like blood or semen stains, hair, or items of clothing at the scene of the crime then these items may prove to be valuable sources of DNA of the criminal .Since the year 1987, innumerable cases have been solved with the help of DNA fingerprint evidence.
5. Personal Identification - DNA maybe the best way to identify a person as all body tissues and organs contain the same DNA type. The specimen required also is very small. In fact the US army has been doing DNA fingerprinting of all its soldiers and has a huge databank. The DNA method for personal identification is far superior to the dental records and blood typing methods that were popularly being used.
A boon to solving criminal cases
Unlike a conventional fingerprint that occurs only on the fingertips and can be altered by surgery, a DNA fingerprint is the same for every tissue , and organ of a person . It cannot be altered by any known treatment .
Three years later, 15 year old Dawn Ashworth was similarly sexually attacked and slain within a few hundred yards of the first crime and semen was again recovered from a vaginal swab. Richard Buckland, a 17 year old kitchen worker who had known the victim was arrested and after extensive
interrogation, confessed to the rape and murder.
The Lynda Mann was reopened and the samples were sent to a Professor Alec Jeffreys at a nearby university. He had developed the novel technique of DNA fingerprinting and using it, he concluded that both girls had been raped by
the same man, but the man was not Buckland. Infact, Buckland mentally a bit dull and easily confused -had not even fit into the 10 % class of possible suspects.
Men and teenage boys in Narborough and nearby villages were asked voluntarily submit to blood drawing and any blood that met the right criteria was sent to the Professor for analysis. The police hoped that this massive undertaking would somehow flush out the killer. After thousands of samples nothing turned up.
Colin Pitchfolk, a 28 year old bakery worker who was well known for creative cake decoration had not given blood when his notice was sent. He had used a falsified identification document regarding his community. This was reported to the police by his coworkers. Pitchfork's blood was the last of 4583 to be drawn and tested. His DNA proved a perfect match to the genetic fingerprint obtained from the semen samples.
The technology today has proved to be so powerful that even the blood-stained clothing of Abraham Lincoln was used and the DNA analyzed for evidence of a genetic disorder called Marfan's Syndrome.
Glossary
DNA - Deoxyribonuclic acid, the chemical name for the molecule of inheritance that directs the growth, organization, development, and function of cells. DNA is found in virtually every cell of every living organism.
Inherited Disorder - A disease caused primarily by changes in a person's DNA, inherited from the parents, rather than some infectious agent or environmental influence.
Semen - Thick, whitish fluid containing sperm that is discharged through the penis during ejaculation
DNA Finger printing
It is widely known that each individual has a DNA profile as unique as a fingerprint. Actually, over 99% of all 3 billion nucleotides in human DNA which we inherit from each parent are identical among all individuals. However, for every 1000 nucleotides that we inherit there is 1 site of variation or polymorphism, in the population. These DNA polymorphisms change the length of the DNA fragments produced by the digestion of restriction enzymes . The resulting fragments are called restriction fragments length polymorphisms (RFLP's--"riflips"). Gel electrophoresis can be used to separate and determine the size of the RFLPs. The exact number and size of fragments produced by a specific restriction enzyme digestion varies from individual to individual.
DNA fingerprinting has proved valuable, not only for convicting felons and exonerating the innocent, but also for establishing maternity or paternity and proving family relationships. More exotic uses include the identification of missing children in Argentina, soldiers killed in war, and even the body of Nazi physician Joseph Mengele, the so-called "Angel of Death."
General Info About DNA Finger Printing *
Unlike a conventional fingerprint that occurs only on the fingertips and can be altered by surgery, a DNA fingerprint is the same for every tissue , and organ of a person . It cannot be altered by any known treatment .
Fingerprinting with ink and paper , based on fingertip ridge patterns is the standard method for personal identification. Finger prints are constant throughout life, finger prints can be used to distinguish one person from any other. Similarly the DNA of every individual is also unique in its own way. Actually the method should be called simply DNA printing or DNA typing since it has nothing to do with the fingers. The degree of variation in bands from one person to another is so large that the theoretical probability that the bands seen in one individual are present in another unrelated individual may
be in millions. The advantages over finger prints are numerous. DNA can be isolated from any part of the body, skin cells, blood or blood stains or semen.
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