DNA Fingerprinting Explained, Techniques Used, Usage, Limitations and Contradictions. *I won an Award for the Best Power Point Project Presentation in class 12th for this project. :D

1. DNA Fingerprinting
Presented By: Disha Bedi
Class XI B
Roll no. 10

2. Kohli, the prime suspect in the rape and murder
of a teenaged British girl Hannah Foster.
The fingerprints and DNA fingerprintingfingerprinting of
Kohli, had confirmed his identity in person.
In NEWS

3. In NEWS
Priyadarshani Mattoo was stalked,raped and murdered
on Jan 23, 1996.
 But the accused,Santosh Kumar Singh, the son of a
police officer, was set free in the absence of any
evidence against him.
DNA Fingerprinting helped Mattoo to receive justice
after 10 years!

4.  NAHAN, Sept 23 98’— For the first time,NAHAN, Sept 23 98’— For the first time,
the HP police has taken the help ofthe HP police has taken the help of DNADNA
fingerprintingfingerprinting to establish the paternity of ato establish the paternity of a
child and thus strengthen a case against achild and thus strengthen a case against a
rape accusedrape accused..
In NEWS

5.  DNADNA fingerprintingfingerprinting was the key inwas the key in
explaining the stains on intern Monikaexplaining the stains on intern Monika
Lweinsky's famous dressLweinsky's famous dress..
In NEWS

6.  At the time of her murder, Madhumita wasAt the time of her murder, Madhumita was
pregnant and the foetus was sent forpregnant and the foetus was sent for DNADNA
fingerprintingfingerprinting ..
In NEWS

7.  DNA fingerprintingDNA fingerprinting confirms HE is Saddam.confirms HE is Saddam.
In NEWS

8.  DNA fingerprintingDNA fingerprinting confirms mad cow came fromconfirms mad cow came from
Canada.Canada.
In NEWS

9. What is this DNA
Fingerprinting about
which the whole
world is talking?

10. What is DNA Fingerprinting?
 DNA fingerprinting, which is also known asDNA fingerprinting, which is also known as DNADNA
typingtyping, is a DNA-based identification system that, is a DNA-based identification system that
relies on genetic differences among individuals orrelies on genetic differences among individuals or
organisms. This technique was developed byorganisms. This technique was developed by AlecAlec
JeffreysJeffreys and his colleagues at Leicester University inand his colleagues at Leicester University in
UK.UK.
 Every living thing (except identical twins, triplets,Every living thing (except identical twins, triplets,
and so on) isand so on) is genetically uniquegenetically unique . This is due to the. This is due to the
order in which DNA base pairs are sequenced..order in which DNA base pairs are sequenced..
Sequences of DNA differ from person to person, butSequences of DNA differ from person to person, but
every cell within the same person contains the sameevery cell within the same person contains the same
sequence of DNA.sequence of DNA.
 On some human chromosomes, there are sequencesOn some human chromosomes, there are sequences
of repeated DNA (9 to 80 base pairs long). Theseof repeated DNA (9 to 80 base pairs long). These
sequences are calledsequences are called VariableVariable Number of TandemNumber of Tandem
Repeats (VNTRs).Repeats (VNTRs). The VNTR of two persons mayThe VNTR of two persons may
be of the same length and sequences at certain sitesbe of the same length and sequences at certain sites
but vary at others.but vary at others.

11. DNA(deoxyribosnucleic acid)
DNA. It's what makes you unique. It's the stuff that tells each and every one
of your body's 10 trillion cells what it's supposed to be and what it's supposed
to do.
 And although your DNA is different from that of every other person in the
world -- unless you have an identical twin -- it's the same in every cell that
makes up your body. That DNA is unique from person to person but the same
from cell to cell in one person can be a handy thing, especially when it comes
to DNA fingerprinting.
Genetic fingerprinting, DNA testing, DNA typing, and DNA profiling are
techniques used to distinguish between individuals of the same species using
only samples of their DNA.
Two humans will have the vast majority of their DNA sequence in common.
Genetic fingerprinting exploits highly variable repeating sequences called
minisatellites. Two unrelated humans will be likely to have different numbers of
minisatellites at a given locus. By using PCR(Polymerase Chain Reaction)enough
DNA is obtained to then detect the number of repeats at several loci.

12. Bases In DNA
DNA consists of four bases:-
A (Adenine)
T (Thymine)
G (Guanine)
C (Cytosine)
Base A on one strand binds with T on the other
strand and vice versa. Base G on one strand binds
with C on the other.
Difference in base and DNA sequence is the
basic principle used in DNA fingerprinting.

13. Discovering DNA Fingerprinting
DNA fingerprinting has become an indelible part of society, helping to prove
innocence or guilt in criminal cases, resolving immigration arguments and
clarifying paternity.
It was invented by Professor Sir Alec Jeffreys at University of Leicester, UK.
He had got to the point where we could detect single copies of human genes –
which led to one of the first observations of introns [non-coding sections of DNA
that split up genes]. But when he went to Leicester in 1977, he wanted to move
away from the study of split genes, and to marry the new techniques of molecular
biology with human genetics.
Professor Jeffreys's plan was to use the primitive gene
detection methods of the time to look at structures of genes
and understand inherited variation – the variation between
people.

14. Discovering DNA Fingerprinting
(cont.)
 While RFLPs were proof ofWhile RFLPs were proof of inherited variationinherited variation at the DNA level, they wereat the DNA level, they were
difficult to find and to assay, and did not tell you much about variation betweendifficult to find and to assay, and did not tell you much about variation between
people – you either had the change or you didn't.So Professor Jeffreys startedpeople – you either had the change or you didn't.So Professor Jeffreys started
looking for pieces of DNA that would belooking for pieces of DNA that would be more variable than SNPsmore variable than SNPs..
 A prime candidate wasA prime candidate was tandem repeat DNAtandem repeat DNA – where a short sequence of DNA was– where a short sequence of DNA was
repeated many times in a row.Intuitively it seemed that regions of tandemlyrepeated many times in a row.Intuitively it seemed that regions of tandemly
repeated DNA would be open to mutation processes such as duplication andrepeated DNA would be open to mutation processes such as duplication and
recombination.They could be highly variable, informative geneticrecombination.They could be highly variable, informative genetic makers.makers.
An early outcome of this research was one of the first descriptions of a restriction
fragment length polymorphism (RFLP). (DNA-cutting enzymes target short DNA
sequences, and chop the genome into pieces. Some people have a small DNA change
– a single nucleotide polymorphism [SNP] – in a target site, preventing the enzymes
cutting the DNA at that site.)

15. The first DNA Fingerprint
The true story of DNA fingerprinting started at the headquarters of the British
Antarctic Survey in Cambridge.
 Professor Jeffreys collected a big lump of seal meat from their lock-up freezer
and got the seal myoglobin gene, had a look at human myoglobin gene and
there, inside an intron in that gene was tandem repeat DNA – a minisatellite.
 This minisatellite was to prove the key to the rest of the genome, for while it
was not variable itself, its sequence was similar to the very few minisatellites
that had been described previously.
 Using the myoglobin minisatellite as a 'hook', the team could then identify
more minisatellites and to their surprise discovered a core sequence - a piece of
DNA that is similar in many different minisatellites.
 Using the core sequence they made a probe that latched onto lots of these
minisatellites at the same time and, to test out the system they hybridised the
probe to a blot with DNA from several different people.

16. The first DNA Fingerprint
(cont.)
On a Monday morning in September
1984, the X-ray of the blot was developed
in the Leicester University darkroom.
The team realised they had patterns.
There was a level of individual
specificity.The potential of DNA
fingerprinting was clear.
 Two to three months later, the grubby
mess of the first fingerprint had been
refined into clean patterns where DNA
fingerprints, unique to an individual, could
be deciphered clearly.
 DNA fingerprinting was ready for prime
time.

17. Reference samples
DNA identification must be done by an extractionDNA identification must be done by an extraction
of DNA from substances such as:of DNA from substances such as:
 Personal items (e.g. toothbrush, razor, ...)Personal items (e.g. toothbrush, razor, ...)
 Banked samples (e.g. banked sperm or biopsyBanked samples (e.g. banked sperm or biopsy
tissue)tissue)
 Blood kin (biological relative)Blood kin (biological relative)
 Human remains previously identifiedHuman remains previously identified
Reference samples are often collected usingReference samples are often collected using buccalbuccal
swabswab..

18. DNA Typing Techniques
 Scientists have developedScientists have developed three main techniquesthree main techniques to lookto look
directly at minute differences in genes.directly at minute differences in genes.
 Each technique has it’s advantages and disadvantages, andEach technique has it’s advantages and disadvantages, and
are used in basic and applied research.are used in basic and applied research.
 The technique of choice depends upon the question beingThe technique of choice depends upon the question being
asked,asked, amount of DNA available, capability to minimizeamount of DNA available, capability to minimize
contamination, cost and urgencycontamination, cost and urgency. Sometimes the. Sometimes the
techniques are used in combination.techniques are used in combination.

19. DNA Typing Techniques
(cont.)
 To successfully identify minute differences in DNATo successfully identify minute differences in DNA
molecules, scientists must focus DNA-typing techniquesmolecules, scientists must focus DNA-typing techniques
on regions of the DNA molecule that areon regions of the DNA molecule that are highly variablehighly variable
between two individuals.between two individuals.
 This is one of the reasons they often useThis is one of the reasons they often use DNA fromDNA from
mitochondriamitochondria instead of nuclear DNA, which does not tendinstead of nuclear DNA, which does not tend
to vary as much from one individual to the next.to vary as much from one individual to the next.
 Another reason for using mitochondrial DNA is itsAnother reason for using mitochondrial DNA is its uniqueunique
inheritance patterninheritance pattern; virtually all is inherited from the; virtually all is inherited from the
female parent.female parent.

20. 1.RFLP DNA Typing
 One technique, known asOne technique, known as restriction fragment length polymorphismrestriction fragment length polymorphism
(RFLP)(RFLP), uses naturally occurring enzymes that cut DNA at very precise, uses naturally occurring enzymes that cut DNA at very precise
locations.locations.
 Because of differences in the sequence of nucleotides, the enzymes cutBecause of differences in the sequence of nucleotides, the enzymes cut
DNA samples from different individuals in different places.DNA samples from different individuals in different places.
 The cut fragments of DNA are of different sizes and compose a DNAThe cut fragments of DNA are of different sizes and compose a DNA
pattern, or "pattern, or "fingerprintfingerprint," unique to each individual.," unique to each individual.
 Comparing the different-sized DNA fragmentsComparing the different-sized DNA fragments of two samples provides aof two samples provides a
very strong evidence about whether or not the two samples came from avery strong evidence about whether or not the two samples came from a
single source or individual.single source or individual.
 This approach to DNA typing required quite large samples ofThis approach to DNA typing required quite large samples of
biological material in order to obtain reasonable results.biological material in order to obtain reasonable results.

21. RFLP DNA Typing (cont.)
 Extraction-Extraction-The first step in DNA typing is extraction of the DNA from theThe first step in DNA typing is extraction of the DNA from the
sample, be it sample blood, saliva, semen or some other biological stain.sample, be it sample blood, saliva, semen or some other biological stain.
 Production of Restriction Fragments. –Production of Restriction Fragments. –
The purified DNA is then cut into fragments byThe purified DNA is then cut into fragments by RESTRICTION ENZYMES.RESTRICTION ENZYMES.
Take the pattern GCGC and imagine it occurs more than once in the DNA. TheTake the pattern GCGC and imagine it occurs more than once in the DNA. The
number of times it occurs is unique to the individual. The restriction enzymenumber of times it occurs is unique to the individual. The restriction enzyme
chops the DNAchops the DNA in two at every place where the GCGC pattern occurs;in two at every place where the GCGC pattern occurs;
Person 1 has the repeat sequence three times while Person 2 has it twice. ThePerson 1 has the repeat sequence three times while Person 2 has it twice. The
restriction enzyme will cut between the first G and the first C.restriction enzyme will cut between the first G and the first C.

22. RFLP DNA Typing (cont.)

ElectrophoresisElectrophoresis --The restriction fragments have negative charge and canThe restriction fragments have negative charge and can
be separated by a technique calledbe separated by a technique called GEL ELECTROPHORESISGEL ELECTROPHORESIS, which, which
separates the pieces of DNA based on their size.separates the pieces of DNA based on their size.
The samples of DNA that have been treated with restriction enzymes areThe samples of DNA that have been treated with restriction enzymes are
placed in separate lanes on aplaced in separate lanes on a slab of electrophoretic gelslab of electrophoretic gel across which isacross which is
placed anplaced an electric fieldelectric field. The fragments migrate towards the positive. The fragments migrate towards the positive
electrode, the smaller fragments moving faster than the larger fragments, thuselectrode, the smaller fragments moving faster than the larger fragments, thus
separating the DNA samples into distinct bands.separating the DNA samples into distinct bands.
■ DetectionDetection --The bands can be visualizedThe bands can be visualized
usingusing luminescentluminescent dyesdyes.

23. 2.PCR DNA Typing
 Another DNA typing technique, theAnother DNA typing technique, the polymerase chain reaction (PCR).polymerase chain reaction (PCR).
 It makes use of the process by which cells duplicate their DNA beforeIt makes use of the process by which cells duplicate their DNA before
they divide into two cells. PCR makesthey divide into two cells. PCR makes thousands of copiesthousands of copies of a specificof a specific
DNA sequence in a matter of hours.DNA sequence in a matter of hours.
 PCR, like restriction analysis, allows usPCR, like restriction analysis, allows us to compare two DNA samplesto compare two DNA samples toto
see if they come from the same individual, but it also allows us to detectsee if they come from the same individual, but it also allows us to detect
the presence or absence ofthe presence or absence of particular bits of DNAparticular bits of DNA in a sample.in a sample.

24. 3. AmpFLP
Another technique, AmpFLP, or Amplified Fragment Length Polymorphism
was also put into practice during the early 1990's. This technique was also faster
than RFLP analysis and used PCR to amplify DNA samples.
 It relied on variable number tandem repeat (VNTR) polymorphisms to
distinguish various alleles, which were separated on a polyacrylamide gel using
an allelic ladder (as opposed to a molecular weight ladder). Bands could be
visualized by silver staining the gel. One popular locus for fingerprinting was
the D1S80 locus.
. As with all PCR based methods, highly degraded DNA or very small amounts
of DNA may cause allelic dropout (causing a mistake in thinking a heterozygote
is a homozygote) or other stochastic effects. In addition,
because the analysis is done on a gel, very high number repeats
may bunch
together at top of gel, making it difficult to resolve.
 AmpFLP analysis can be highly automated, and allows
for easy creation of phylogenetic trees based on comparing
individual samples of DNA.

25. DNA Fingerprinting Usage
 Forensic UseForensic Use
 PaternityPaternity
 AnthropologyAnthropology
 Wild life managementWild life management
 Diagnosis of Inherited DisordersDiagnosis of Inherited Disorders

26. Forensic Use
 InIn criminal investigationscriminal investigations, DNA from samples of hair,, DNA from samples of hair,
bodily fluids or skin at a crime scene are compared withbodily fluids or skin at a crime scene are compared with
those obtained fromthose obtained from suspected perpetratorssuspected perpetrators..
 A skin cell, blood, and the shaft of a hair (shown from leftA skin cell, blood, and the shaft of a hair (shown from left
to right) all contain DNA and can be collected as crimeto right) all contain DNA and can be collected as crime
scene evidence. (Microscopic images of the skin cell andscene evidence. (Microscopic images of the skin cell and
hair shafthair shaft..

27. Forensic Use (cont.)
 DNA typing was first used inDNA typing was first used in Great BritainGreat Britain for lawfor law
enforcement purposes in the mid-1980s.enforcement purposes in the mid-1980s.
 DNA typing has reaped positive return in manyDNA typing has reaped positive return in many
cases.cases.
 DNA typing has exonerated innocent individuals forDNA typing has exonerated innocent individuals for
crimes they were convicted of before DNAcrimes they were convicted of before DNA
fingerprinting became available.fingerprinting became available.
 There isThere is acceptanceacceptance of DNA typingof DNA typing by court.by court.

28. Paternity
 Paternity determination is possible with DNA typingPaternity determination is possible with DNA typing
becausebecause half of the father's DNAhalf of the father's DNA is contained in theis contained in the
child's genetic material.child's genetic material.
 Using restriction analysis, DNA fingerprints of theUsing restriction analysis, DNA fingerprints of the
mother, child and alleged father are compared.mother, child and alleged father are compared.
 The DNA fragments from the mother that match theThe DNA fragments from the mother that match the
child's are ignored in the analysis.child's are ignored in the analysis.
 To establish paternity, the remaining DNA fragmentsTo establish paternity, the remaining DNA fragments
in the child's DNA fingerprint, which have beenin the child's DNA fingerprint, which have been
inherited from the biological father, are theninherited from the biological father, are then
compared to the DNA sequences of the alleged father.compared to the DNA sequences of the alleged father.

29. Paternity (cont.)
In this example daughter 2 is the child from the mother’s previous
marriage and son 2 is adopted.Both daughter 1 and son 1 share RFLPs
with both the mom and dad (coloured blue and yellow respectively),
while daughter 2 has RFLPs of the mom but not the dad, and son 2 does
not
have RFLPs from either parent.
In this example, a family consists of a mom and dad, two daughters and
two sons. The parents have one daughter ,one son and one daughter
from the mother’s previous marriage.

30. Anthropology
 Scientists are using DNA typing to help piece together theScientists are using DNA typing to help piece together the
thousands of fragments gathered from thethousands of fragments gathered from the Dead SeaDead Sea
ScrollsScrolls..
 DNA typing can determine the degree of relatednessDNA typing can determine the degree of relatedness
amongamong human fossilshuman fossils from different geographic locationsfrom different geographic locations
and geologic eras. The results shed light on the history ofand geologic eras. The results shed light on the history of
human evolution.human evolution.
 Scientists used DNA fingerprinting to identify the remainsScientists used DNA fingerprinting to identify the remains
ofof Czar Nicholas Romanov II of RussiaCzar Nicholas Romanov II of Russia and his family,and his family,
executed by the Bolsheviks in 1918. They compared DNAexecuted by the Bolsheviks in 1918. They compared DNA
from bones with DNA from blood samples of livingfrom bones with DNA from blood samples of living
descendants of Nicholas II. The results of DNA typingdescendants of Nicholas II. The results of DNA typing
disproved one woman's claim that she was the Russiandisproved one woman's claim that she was the Russian
Grand Duchess Anastasia and had survived the RomanovGrand Duchess Anastasia and had survived the Romanov
massacre.massacre.

31. Wildlife Management
 The more we understand about the geneticThe more we understand about the genetic
makeup of natural populations, the better ourmakeup of natural populations, the better our
conservation and management plans will be.conservation and management plans will be.
 Scientists use DNA typing toScientists use DNA typing to
 measure the amount ofmeasure the amount of genetic variationgenetic variation
between different populations of a speciesbetween different populations of a species
 determine thedetermine the geographic distributionsgeographic distributions ofof
species, help preserve endangered orspecies, help preserve endangered or
threatened speciesthreatened species
 determine thedetermine the genetic resiliencegenetic resilience of wildof wild
populations of endangered species.populations of endangered species.
 For example, we now know thatFor example, we now know that cheetahscheetahs are atare at
risk of extinction largely because there is virtuallyrisk of extinction largely because there is virtually
no genetic variation in the species.no genetic variation in the species.

32. Wildlife Management (cont.)
 DNA typing recently helped scientists solve theDNA typing recently helped scientists solve the
mystery of themystery of the Mexican group of Pacific loggerheadMexican group of Pacific loggerhead
turtlesturtles. Pacific loggerheads nest in Japan and. Pacific loggerheads nest in Japan and
Australia, not in Mexico, yet very young loggerheadsAustralia, not in Mexico, yet very young loggerheads
are often found off the Mexican coast.are often found off the Mexican coast.
 Biologists assumed the young loggerheads could notBiologists assumed the young loggerheads could not
have swum the 10,000 miles fromhave swum the 10,000 miles from Japan to MexicoJapan to Mexico,,
and even farther from Australia, so the origin of theand even farther from Australia, so the origin of the
Mexican loggerheads was a mystery.Mexican loggerheads was a mystery.
 Using DNA typing, however, biologists establishedUsing DNA typing, however, biologists established
that the young loggerheads in Mexico are, in fact,that the young loggerheads in Mexico are, in fact,
born in Australia or Japan, are carried to Mexico byborn in Australia or Japan, are carried to Mexico by
ocean currents, and then swim back to Australia orocean currents, and then swim back to Australia or
Japan when they are ready to breed.Japan when they are ready to breed.

33. Wildlife Management (cont.)
 DNA fingerprinting has also been used toDNA fingerprinting has also been used to
monitormonitor illegal trade in protected species.illegal trade in protected species.
 For example, scientists determined thatFor example, scientists determined that fishfish
productsproducts on sale in Japan included whale meaton sale in Japan included whale meat
that had been illegally imported, as well asthat had been illegally imported, as well as
other species that had been hunted illegally.other species that had been hunted illegally.
 Similar studies conducted on ivory uncoveredSimilar studies conducted on ivory uncovered
elephant poachingelephant poaching in countries where it isin countries where it is
illegal.illegal.
 Finally, some countries, including the UnitedFinally, some countries, including the United
States, are using DNA typing to prevent theStates, are using DNA typing to prevent the
importation ofimportation of caviar from endangeredcaviar from endangered
sturgeon species.sturgeon species.

34. Diagnosis of Inherited Disorders
 DNA fingerprinting is used to diagnose inheritedDNA fingerprinting is used to diagnose inherited
disorders in both prenatal and newborn babies indisorders in both prenatal and newborn babies in
hospitals around the world. These disorders mayhospitals around the world. These disorders may
includeinclude cystic fibrosis, hemophilia, Huntington'scystic fibrosis, hemophilia, Huntington's
disease, familial Alzheimer's, sickle cell anemia,disease, familial Alzheimer's, sickle cell anemia,
thalassemia, and many others.thalassemia, and many others.
 Early detection of such disorders enables theEarly detection of such disorders enables the
medical staff to prepare themselves and the parentsmedical staff to prepare themselves and the parents
for proper treatment of the child. In some programs,for proper treatment of the child. In some programs,
genetic counselors use DNA fingerprint informationgenetic counselors use DNA fingerprint information
to help prospective parents understand theto help prospective parents understand the risk ofrisk of
having an affected childhaving an affected child. In other programs,. In other programs,
prospective parents use DNA fingerprintprospective parents use DNA fingerprint
information in their decisions concerning affectedinformation in their decisions concerning affected
pregnancies.pregnancies.

35. Developing Cures for Inherited
Disorders
•Research programs to locate inherited
disorders on the chromosomes depend on the
information contained in DNA fingerprints.
•By studying the DNA fingerprints of
relatives who have a history of some
particular disorder, or by comparing large
groups of people with and without the
disorder, it is possible to identify DNA
patterns associated with the disease in
question.
•This work is a necessary first step in
designing an eventual genetic cure for these
disorders

36. A story on DNA Fingerprinting
On the evening of November 1, at approximately 8:15 p.m., Jimmy Sweet
entered his bedroom, walked over to his desk, and sat down at his computer.
While reaching for the computer's switch he noticed, out of the corner of his eye,
that one of the items on a typically well-organized shelf was out of place.
Jimmy shot across the room for a closer examination.
Sure enough, the object in question had indeed been
disturbed.
The object had been sealed in an air-tight package.
The package was now ripped open. The object was
still inside, but it was no longer in its original
condition. In Jimmy's eyes, it was now worthless.

37. Story (cont.)
Jimmy pulled out what had been his most-valued possession -- his holographic
NOVA lollipop. The confectionery treat was now a sticky mess. Someone had
obviously indulged him- or herself in its sugary molecules. The lollipop's
holographic image had been licked away.
THE SUSPECTS
The prime suspects in this case are Jimmy's seven sisters: Candy, Cookie,
Sugar, Lolly, Honey, Brandee, and Carmela. Each one of these sisters is a
notorious candy lover and is easily capable of committing this crime of
confection.
The suspects have been detained. DNA fingerprints of each are available.

38. Story (cont.)
Fortunately for this case, a lollipop cannot be licked without leaving behind a bit of
saliva. A DNA fingerprint from the saliva is taken which was left on the lollipop.
Then the fingerprint is used to single out the culprit of this crime The DNA specimen
on the lab countertop has already been prepared, using some of the saliva extracted
from the lollipop.
The DNA fingerprint of the culprit is compared with DNA fingerprint of the seven
sisters. The fingerprint of Cookie matches the fingerprint of the culprit. So Cookie
was the one who licked Jimmey’s lollypop.
Isn’t it amasing that the culprit could be found from only a single stain of saliva.

39. LIMITS of DNA Fingerprinting
 But DNA fingerprinting does not helpBut DNA fingerprinting does not help
every convict who asks for it. Inevery convict who asks for it. In
September, 2000,September, 2000, Derek BarnebeiDerek Barnebei waswas
executed in Virginia for raping andexecuted in Virginia for raping and
murdering his girlfriend. The test he'dmurdering his girlfriend. The test he'd
sought located his DNA in tissue takensought located his DNA in tissue taken
from under the victim's fingernails after thefrom under the victim's fingernails after the
1993 crime. Barnebei claimed innocence to1993 crime. Barnebei claimed innocence to
death.death.
 It is "It is "not a panaceanot a panacea for every case, it mayfor every case, it may
not be involved in a simple shooting, wherenot be involved in a simple shooting, where
somebody dies but there are no bodilysomebody dies but there are no bodily
fluids left." There's also a disturbingfluids left." There's also a disturbing
possibility that DNA fingerprinting couldpossibility that DNA fingerprinting could
finger thefinger the wrong personwrong person -- if labs make-- if labs make
mistakes, or if cops plant evidence or lie onmistakes, or if cops plant evidence or lie on
the witness stand. Such allegations --the witness stand. Such allegations --
although they do not concern capital casesalthough they do not concern capital cases
-- are the focus of the ongoing Los Angeles-- are the focus of the ongoing Los Angeles
police scandalpolice scandal

40. CONTRADICTIONS against
DNA Fingerprinting
1.1. Should an individual have the right toShould an individual have the right to
refuse torefuse to give a blood samplegive a blood sample for DNAfor DNA
analysis, or should the authorities have theanalysis, or should the authorities have the
right to takeright to take suchsuch samples withoutsamples without
permissionpermission??
2.2. Biotechnologists want to map the DNA ofBiotechnologists want to map the DNA of
thethe entire human populationentire human population. How would. How would
this help us? What problems could itthis help us? What problems could it
create?create?

41. DNA Fingerprinting will go
a long way in providing the
justice in courtrooms and in
many other areas as has
been summarized earlier.
But one also has to think
about its limitations and the
contradictions against it.