Dna Fingerprinting Technology

8/2/2019 Dna Fingerprinting Technology

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DNAFINGERPRINTING

TECHNOLOGYBy Kanika Sori

B.Tech (BT), 2nd year

10111015


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WHATISDNAFINGERPRINTING?

In genetics, DNA Fingerprinting or DNA profiling is amethod of isolating and making images ofsequences of DNA.

It is a technique used by scientists to distinguishbetween the individuals of the same species usingonly samples of their DNA.


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WHOINVENTEDIT?

It was at 9am on Monday September 15, 1984 when SirAlec Jeffreys experienced a rare, serendipitous momentin science while removing some X-ray film from itsdeveloping tank.

He had been looking for good genetic markers for basicgenetic analysis, but had accidentally stumbled upon away of establishing a human's genetic identification.

By that afternoon, he and his colleagues had namedtheir discovery DNA fingerprinting.

His technique has subsequently been applied to a widerange of problems in genetics. These include developinggenetic markers for medical research and the diagnosisof inherited disorders.


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DNA FINGERPRINT TECHNIQUE

Different individuals carry different alleles.

Most alleles useful for DNA fingerprinting differ on thenumber of repetitive base sequences they contain.

Stage 1: Cells are broken down to release DNA. If only

small amount of DNA is available it can be amplifiedusing PCR.

Stage 2: DNA is cut with a restriction enzyme thatrecognizes sites on either side of the region that varies,

DNA fragments of different sizes will be produced. A DNA fingerprint is made by analyzing the different

sizes of DNA fragments produced from a number ofdifferent sites that vary within the genome.


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Stage 3: Fragments are separated on the basis ofsize using Gel Electrophoresis.

DNA being negatively charged moves towards the

anode.


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A radioactive substance is added which combineswith the DNA fragments to produce a fluorescentimage.

A photographic copy of the DNA bands is obtained.

Stage 4: The pattern of fragment distribution is thenanalyzed.


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RESULTS

In a standard DNA fingerprint, as many as a dozensites can be analyzed with each site having manypossible combinations of alleles.

When many genes are analyzed, each with manydifferent alleles the chance that two sites will matchis 1 in 100 billion when no lab err is factored in.


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Unlike a conventional fingerprint that occurs only on the fingertips andcan be altered by surgery, a DNA fingerprint is the same for every cell,tissue, and organ of a person. It cannot be altered by any knowntreatment. Consequently, DNA fingerprinting is rapidly becoming theprimary method for identifying and distinguishing among individual

human beings.


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DNA FINGERPRINTINGCANBEUSEDINPATERNITYTESTINGORMURDERCASES


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An additional application of DNA fingerprinttechnology is the diagnosis of inherited disorders inadults, children, and unborn babies.

It is also used in breeding programs in a number ofzoos and conservation centers to establish familyrelationships within captive colonies of endangeredspecies of animals and birds to minimize inbreeding

and maintain genetic diversity. The technology is so powerful that, for example,

even the blood-stained clothing of Abraham Lincolncould be analyzed for evidence of a genetic

disorder called Marfan's Syndrome.


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Many have questioned the validity of DNA fingerprinting testresults. Because the burden of proof is on the forensic scientists,there are safeguards in place to be sure that DNA fingerprintingresults are accurate. The first is the control DNA that runs

through the tests alongside the suspect's DNA and the DNA foundat the crime scene. If the control DNA tests properly, then theDNA in question tests properly as well. Another safeguard inplace is that the test is run four times using four differentrestriction enzymes. In order to be absolutely positive of a match,all four sets of DNA from the crime scene must match all four sets

of DNA from the suspect. With these safeguards in place, theodds are one in 70 billion (140 times Earth's population) that theresults are inaccurate.

PROBLEMSWITH DNA TESTING


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REFERENCES

Rosner, D. 2004. How Does DNA Fringerprinting Work?http://www.thenakedscientists.com/HTML/articles/article/dalyacolumn8.htm/

Sha, K. 2004. How Does a DNA Paternity Test Work?http://www.thetech.org/genetics/ask.php?id=20

Author Unknownhttp://fig.cox.miami.edu/~cmallery/150/gene/mol_gen.htm
http://www.thenakedscientists.com/HTML/articles/article/dalyacolumn8.htm/http://www.thenakedscientists.com/HTML/articles/article/dalyacolumn8.htm/http://www.thetech.org/genetics/ask.php?id=20http://fig.cox.miami.edu/~cmallery/150/gene/mol_gen.htmhttp://fig.cox.miami.edu/~cmallery/150/gene/mol_gen.htmhttp://fig.cox.miami.edu/~cmallery/150/gene/mol_gen.htmhttp://www.thetech.org/genetics/ask.php?id=20http://www.thetech.org/genetics/ask.php?id=20http://www.thenakedscientists.com/HTML/articles/article/dalyacolumn8.htm/http://www.thenakedscientists.com/HTML/articles/article/dalyacolumn8.htm/

Dna Fingerprinting Technology

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