DNA AND CELL BIOLOGY
Volume 25, Number 3, 2006
© Mary Ann Liebert, Inc.
Pp. 181–188
DNA Fingerprinting in the Criminal Justice System:
An Overview
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ABSTRACT
DNA fingerprinting is a powerful technology that has revolutionized forensic science. No two individuals can
have an identical DNA pattern except identical twins. Such DNA-based technologies have enormous social implications and can help in the fight against crime. This technology has experienced many changes over time
with many advancements occurring. DNA testing is a matter of serious concern as it involves ethical issues.
This article describes various trends in DNA fingerprinting and the current technology used in DNA profiling, possible uses and misuses of DNA databanks and ethical issues involved in DNA testing. Limitations and
problems prevailing in this field are highlighted.
INTRODUCTION
K
ING SOLOMON’S STORY is well known for his famous decision in a maternity dispute, but today, parentage decisions are relatively easy with the assistance of DNA technology. DNA technology was first developed in England in 1985
by Sir Alec Jeffreys. This technology, so named because DNA
is used for identification rather than latent physical fingerprints,
gives a unique and specific profile similar to a thumb impression (Jeffreys et al., 1985). DNA fingerprinting technology today has made it possible to identify the source of biological
samples found at a crime scene and also to resolve disputes of
paternity and other criminal cases.
Ninety-five percent of the human genome is noncoding
DNA, with only 5% coding for protein region. These noncoding regions are also called “junk” DNA, and are abundant where
the number of repeats show variations among individuals. These
DNA polymorphisms change the length of the DNA fragments
produced by the digestion of restriction enzymes.
A DNA fingerprint is constructed by first extracting a DNA
sample from biological sample. The sample is then cut at specific sites with restriction enzymes, and the segments are
arranged by their molecular size using electrophoresis. The segments are labeled with probes and exposed to X-ray film, where
they form a characteristic pattern, that is, the DNA fingerprint.
If the DNA fingerprints produced from two different samples match, the two samples probably came from the same person. The exact number and size of the fragments produced by
a specific restriction enzyme digestion varies from individual
to individual.
In 1985, police in the UK for the first time used forensic
DNA profiling (http://www.crimtrac.gov.au/dnahistory.htm),
and in the United States, the first criminal conviction based on
DNA evidence occurred in 1988. In 1992, the National Research Council of the United States found that DNA testing was
a reliable method for the identification of criminal suspects, and
the technology rapidly entered the mainstream court system.
The DNA evidence obtained is powerful, since it can implicate
or exonerate a suspect. Currently, DNA testing is routinely used
in civil and criminal cases.
DNA ANALYSIS
Early markers
Karl Landsteiner, in 1901, discovered ABO blood grouping
in humans (Landsteiner, 1901). A set of blood group markers
(red cell antigens and serum protein) were also used to identify
victims and suspects in crime cases. As the polymorphism was
very limited in ABO blood grouping, it was neither informative nor very suitable for excluding a person as a suspect in a
criminal case. The advent of DNA-based markers has now revolutionized the field of forensic science, as it can measure an
unlimited extent of polymorphisms sufficient to differentiate
one individual from another.
Laboratory of DNA Fingerprinting Services, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India.
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Hybridization based multilocus and single locus DNA
profiling
The use of DNA fingerprinting in forensic science had been
suggested in the early 1980s by Prof. Alec Jeffreys using restriction fragment-length polymorphism (RFLP). There was
great enthusiasm among the forensic science community for the
discovery of the minisatellite approach for specific identification (Wong et al., 1987).
Eukaryotic genomes contain a large number of repeated
DNA sequences. These regions are often referred to as satellite
DNA. The core repeat unit for a medium-length repeat, sometimes referred to as a minisatellite or variable number of tandem repeats (VNTR) is in the range of approximately 10–100
bases in length.
VNTR patterns are inherited and are unique (Weising, et al.,
1995). The more VNTR probes used to analyze a person’s
VNTR pattern, the more distinctive and individualized that pattern, or DNA fingerprint, will be. The children will inherit the
different combinations of paternal and maternal VNTRs, and
therefore their profile will be different from each other except
identical twins as shown in Figure 1.
DNA regions with repeat units that are 2–6 bp in length are
called mcrosatellites, simple sequence repeats (SSRs) or short
tandem repeats (STRs). STRs consisted of microsatellites of
small repeating units, two to five bases in length, with a maximum length of around 300 bases, which show a high degree of
polymorphism. Specific microsatellites can be isolated using hybridized probes followed by their sequencing. SSRs can be detected by specific dyes or by radiolabeling using gel electrophoresis. The advantage of using SSRs as molecular markers
is the extent of polymorphism shown, which enables the detection of differences at multiple loci between strains (Butler, 2001).
Hybridization-based DNA fingerprinting involves the use of
two types of probes called multilocus probes (MLP), which identify repeating sequences in genomic DNA digested by restriction enzymes followed by Southern blot analysis at low stringency conditions. The radio labeled probes hybridize with a
series of tandemly repeated sequences with a size range greater
than 20 kb. The resulting autoradiographs consist of a ladderlike series of bands that will be identical only for identical twins
as shown in Figure 2. The fact that DNA is a very stable molecule makes this technology more effective, and even old cases
FIG. 2. Multilocus DNA profiling of (a) Identical and (b)
nonidentical twins.
also can be reviewed. This is equally good for archived specimens. The MLP system, however, was not very successful. The
method was demanding and the results were not suited for inclusion in computer databases. After the advent of the single locus probe (SLP) the technology substantially progressed. In the
SLP system probes were isolated, which identified repeat sequences in individual minisatellites using high stringency conditions to produce a maximum of two bands per probe. Although
the targeted minisatellites showed considerable variation in their
repeat numbers, a single locus was not sufficient for individualization. A number of such loci were analyzed (Lalji, 1991).
PCR-based DNA profiling
In the early 1990s, the DNA fingerprinting technology took
a dramatic change with the advent of the polymerase chain reaction (PCR), a technique that enabled amplification from tiny
amounts of template DNA. The method was fast, reliable, and
was efficient to work even with degraded samples. In the PCRbased technique the time required to analyze a sample was significantly reduced (Weber and May, 1989). It was found to be
more suitable than the previously used MLP and SLP systems.
There was a period when both SLP and PCR-based methods
were used to identify a person in parallel. PCR technology was
used to type many VNTRs region for forensic purposes. Many
polymorphic loci like D1S80 and HLADQ were used for
analysis. There were many reports claiming that it was not much
useful for forensic purposes (Varsha et al., 1999).
In 1992, the use of a new compatible form of genetic profiling called STRs was proposed. Due to their small size they
were extremely stable, and could be detected even with old and
degraded samples.
In 1998, STR analysis became an established feature of
forensic sciences, which basically involved study of a panel of
polymorphic loci comprising THO1, VWA, FGA, D21S11,
D8S1179, and D18S51, as well as D7S820, D13S317, D5S818,
CSF1P0, D16S539, D2S1338, D19S433, TPOX, with recently
introduced Penta E and Penta D (Edwards et al., 1991).
A flow diagram (Fig. 3) and Table 1 show the progressive
advancements in forensic genetics.
HOW IS DNA TYPING PERFORMED?
FIG. 1.
VNTR distribution in a family.
In criminal cases, samples obtained from crime scene evidence and a suspect are used for DNA extraction and analysis
for the presence of a set of specific DNA markers.
DNA markers are small DNA probes that bind to a complementary sequence in the DNA sample. A distinctive pattern for
an individual is created by a series of probes bound to a DNA
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DNA FINGERPRINTING
FIG. 3. The progress in Forensic genetics. (Diagram reprinted by permission of Mark A. Jobling and Tanita Casci from paper
“Encoded evidence: DNA in Forensic analysis, Mark A. Jobling, Nature reviews/Genetics, Vol 5, Oct 2004.)
sample. Comparing such DNA profiles determines whether the
suspect’s sample matches the evidence sample. If the patterns
match, the suspect may have contributed the evidence sample and
if profiles do not match, the person is assumed innocent. Scientists believe that DNA evidence is far superior to eyewitness accounts, where the chance for correct identification is about 50:50.
A combination of probes used in DNA analysis, gives greater
reliability for profiling. Four to six probes are recommended
for a good DNA profile. The recent new innovation in DNA
chip technology (in which thousands of short DNA sequences
are embedded onto a tiny silicon chip) enables a more rapid,
and less expensive analysis using many more probes (Linacre
and Graham, 2002).
A flowchart is presented in Figure 4, which shows the steps
involved in DNA profiling.
DNA TECHNOLOGIES CURRENTLY USED IN
FORENSIC INVESTIGATION
RFLP is a technique for analyzing the variable lengths of
DNA fragments that result from digesting a DNA sample with
a special kind of restriction endonucleases. Amplification fragment Length polymorphism (AFLP) is a PCR-based derivative
method of RFLP in which sequences are selectively amplified
using primers. It is a reliable and efficient method of detecting
molecular markers. Random amplified polymorphic DNA
(RAPD) is one of the most commonly used primary assays for
screening the differences in DNA sequences of two species of
plants. It involves random amplification (Cooper, 2000). HLADQ analysis was also used for identification for quite long
time (Saiki et al., 1986). With the advancement, these technologies became obsolete and were replaced by various tech-
niques like microsatellite analysis, single nucleotide polymorphisms, etc.
Capillary electrophoresis
Capillary electrophoresis, or CE, is a group of techniques used
to separate a variety of samples. These analyses are performed
in narrow tubes, and can result in the rapid separation of different compounds. DNA typing with STR markers is now widely
used for a variety of applications including human identification. CE instruments, such as genetic analyzers, are the method
of choice for many laboratories which perform STR analysis.
The Genetic Analyzer (Applied Biosystems, Foster City,
CA) is a fluorescence based DNA analysis system utilizing capillary electrophoresis. It has multiple color fluorescence detection capability. This capillary machine is capable of running sequence and fragment analysis (Butler et al., 2004) and is a very
popular method for STR typing. ABI 310 is a single-capillary
TABLE 1.
YEAR-WISE ADVANCEMENT
DNA TYPING
IN
FORENSIC
Year
Developments
1985
1986
1988
1989
RFLP approach was developed by Alec Jeffreys
Automated DNA sequencing was first described
FBI started using RFLP probes for case studies
TWGDAM (Technical Working Group on DNA
Analysis Methods) was established
O.J. Simpson case, which spread the awareness of
DNA; UK DNA database established
Y chromosome STR marker was first described
1995
1997
Source: http://www.denverda.org/legalResource/Overview.pdf.
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A Genescan program was used to compare the individual’s
profile (Fig. 5). In genotyping the alleles are denoted by peaks
rather than bands unlike Genescan and peak height is also taken
into consideration while analyzing the results (Fig. 6, Probability of paternity is 99.999%). The match probabilities obtained
with STR multiplexes are very low, and is more than the world
population. The preferred system for STR genetic typing was via
fluorescent dye-labeled primers and automated DNA sequencers.
Multiplexes are analyzed and typed using automated sequencing
equipment. First multiplex used was quadruplex, which had four
STR regions. The recent multiplex amplifies for 16 loci in a single reaction one out of that is Amelogenin, a gender marker. STR
base provides complete information about different STR markers available (Butler, 2001). Simultaneous amplification and separation of a number of STR loci in a single step is possible here.
Other methods include the use of single nucleotide polymorphs (SNPs), DNA amplification fingerprinting (DAF) and
their offshoots. DNA amplification fingerprinting (DAF) involves amplification of genomic DNA, which is directed by only
one oligonucleotide primer of arbitrary sequence (CaetanoAnolles et al., 1991). While the major efforts were made for detecting markers in genomic DNA, there has also been a considerable effort expanded on methods for typing sequences within
the mitochondrial DNA (mtDNA). Although these results are
not as discriminating as those of the STRs, they can be very useful in cases where skeletal remains, hairs, etc., are the only samples available. There have also been advances in the use of markers which are made specific (Y chromosome), and these have
been used successfully particularly in cases of sexual assault.
Mitochondrial DNA analysis
Degraded samples such as hair, bones, and teeth quite often
lack nucleated cellular material and cannot be analyzed with
STR and RFLP. Mitochondrial DNA analysis (mtDNA) can be
used to examine such DNA samples. mtDNA is extremely valuFIG. 4.
Flowchart of DNA profiling.
instrument. Similarly ABI 3100 is a 16-capillary instrument and
is used in large-scale applications.
Short tandem repeat analysis
STRs have discrete alleles. Variability in STR regions can
be used to distinguish one DNA profile from another (Edwards
et al., 1991). The chance that two individuals will have the same
13-loci DNA profile is about one in one billion. Microsatellite
typing can be multiplexed and semiautomated.
Sophisticated software has been developed for STR analysis to
take sample electrophoretic data through the genotyping process
(Ziegle et al., 1992). This is done in two steps by two different
software programs. Genescan software (Applied Biosystems) is
used to spectrally resolve the dye colors for each peak and to size
the DNA fragments. The resulting pherograms are then imported
into the second software program, Genotyper. This program determines each samples genotype by comparing the sizes of alleles observed in a standard allelic ladder sample to those obtained
at each locus in the DNA sample. Genotyping can be performed
on the Genetic Analyzer with different available models (Ziegle
et al., 1992). These are capillary electrophoresis systems.
FIG. 5. Genescan analysis of STR markers in a paternity case.
Lane 1. DNA profile of the mother; Lane 2. DNA profile of the
child; Lane 3. DNA profile of the father.
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DNA FINGERPRINTING
FIG. 6. Electropherogram of genotype of STR markers in samples of a paternity case. 1. Genotype of the mother; 2. Genotype
of the child; 3. Genotype of the father.
able in such cases, as it has high copy number and has no recombinational events.
Mitochondrial DNA is inherited maternally and does segregate independently. Therefore, it gives an excellent record of
matrilineage. The father’s sperm contributes only nuclear DNA.
Occurrence of heteroplasmy is the special feature of mtDNA.
Comparing the mtDNA profile of unidentified remains with the
profile of a potential maternal relative can be an important technique in investigations on missing persons. Simultaneously, it
can also be used as an important tool for matrilineage and evolutionary studies. Mitochondrial DNA can also help in studying
the variety of human diseases, associated with mitochondrial disorders (Wallace, 1999). SNP outside the hypervariable segments
along with mtDNA can provide us a better tool for typing.
Y-chromosome analysis
Analysis of genetic markers on the Y chromosome is especially useful for tracing relationships among males or for analyzing biological evidence involving multiple male contributors
as in rape cases. There are a total of 219 useful STR markers
available on Y chromosome (Kayser et al., 2004).
Single nucleotide polymorphism typing
SNP are DNA sequence variations that occur when a single
nucleotide (A, T, C, or G) in the genome sequence is changed.
SNPs create mutations in human and can be used as markers.
SNPs have lower heterozygosity compared to STR. It will be
not of much use when the samples are mixed, as SNP is a binary marker. Forensic SNP typing provides considerable assistance to forensic scientists in major disasters (Budowle et al.,
2005). Many polymorphic sites need to be analyzed for the identification of SNPs. Mutation analysis is one of the major thrusts
of functional genomics. Validation of a 21-locus autosomal
SNP multiplex has been performed for forensic identification
purposes (Dixon et al., 2005). Microarrays are used very effi-
ciently for mutation analysis, which helps in monitoring the
whole genome on a single chip and for studying the interactions of thousands of genes simultaneously. In the scientific literature various terminologies have been used to describe this
technology as such as DNA chip, DNA microarray, etc.
(Linacre and Graham, 2002).
Forensic studies are mainly done by commercially developed
autosomal STR multiplexes, autosomal SNPs, and markers on the
Y chromosome and mitochondrial DNA (Jobling and Gill, 2004).
ESTABLISHMENT OF DATABANKS
DNA intelligence databases are modern tools for the executive force investigating crime (Werret, 1997; Hoyle, 1998; Parsoh et al., 1998; Peeren boom, 1998; Schneider, 1998).
DNA forensics databases
The first of the national DNA databases involving STR data
was formed in the UK in 1995. The usefulness of such types
of databases was established during the first 5 years of use of
this technology (Werrett and Sparkes, 1998). By 1998, three
other European countries, Austria, Germany, and The Netherlands had introduced national DNA databases (Martin et al.,
2001). The STR loci used to form these databases were THOI,
VWA, FGA, D8S1179, D18S51, and D21S11. Finland and Norway have introduced a national database in 1999. Sweden has
already a database of unknown crime samples. Belgium, Denmark, Switzerland, France, Italy, Spain, and some east European countries also took steps in this direction. In 1989, the FBI
proposed a national DNA database for North America.
The Austrian DNA intelligence database was inaugurated in
1997. In the United States, the Federal Bureau of Investigation
(FBI) has created a national database of genetic information
called the National DNA Index System. The database contains
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DNA obtained from convicted criminals and from evidence
found at crime scenes.
National DNA databank: CODIS
The COmbined DNA Index System, CODIS, utilizes computer and DNA technologies together. All DNA profiles stored
in CODIS are generated using STR analysis. The current version of CODIS uses two indexes where biological evidence is
recovered from the crime scene. The Convicted Offender index contains DNA profiles of individuals convicted of sex offenses and other violent crimes. The Forensic index contains
DNA profiles developed from crime scene evidence. A computer software will search these two indexes for matching DNA
profiles. Law enforcement agencies compare DNA from biological evidence collected from crime scenes that have no suspect with the DNA profiles stored in the CODIS systems. If a
match is made between a sample and a stored profile, CODIS
can identify the culprit.
This technology is authorized by the DNA Identification Act
of 1994. As of January 2003, the database contained more than
a million DNA profiles in its Convicted Offender Index and
about 48,000 DNA profiles collected from crime scenes but
which have not been connected to a particular offender. This
database can also be used to identify criminals who are responsible for crime in other countries. The FBI uses a standard
set of 13 specific STR regions for CODIS (Budowle et al.,
1998). CODIS is a software program that operates local, state,
and national databases of DNA profiles from convicted criminals and missing persons.
Advantages of DNA databanking
One advantage of a comprehensive and modern national
DNA databank is the capability to perform DNA identification
tests of victims and missing persons in the case of disaster.
It is just a matter of comparison of the profile of the sample
with the databank, as the data is already available and the results are more reliable. Time of investigation as well as cost is
reduced. It is also beneficial to society as it helps the investigator to catch the criminal and exonerate the innocent person.
APPLICATIONS OF DNA FINGERPRINTING
TO PLANTS AND ANIMALS
Plant DNA fingerprinting is defined here as the application
of molecular marker techniques to identify cultivars, but this
also can be helpful in providing evidence in crime cases. RAPD
can be a better choice for identification of plant strains. DNA
profiling of plants can be used in solving civil disputes over the
identity of commercially important cultivars (Kumar et al.,
2001).
The genotypic information is used for identification of animals (Barallon, 1998), forensic analysis (Zehner et al., 1998)
and for tracing specific animals to finished meat products (Varsha et al., 2003), pedigree analysis, selection, and breeding programs. Forensic analysis can be of immense help for poaching
cases and to check the illegal trade of endangered species. The
cytochrome b region had been used for identification of the endangered animal species (Branicki et al., 2003). DNA typing in
plants and animals is again a vast topic, and needs a separate
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TABLE 2.
SOME EXAMPLES OF DNA USE
IDENTIFICATION
FOR
FORENSIC
Criminal identification.
Exonerate persons wrongly accused of crimes.
Identify crime and catastrophe victims in mass disasters.
Establish paternity and other family relationships.
Identify endangered species and can help in wild-life poaching cases.
Match organ donors with recipients in organ transplantation
as kidney transplantation.
Determine pedigree for seed or livestock breeds.
To identify different strains and cultivars and can help in protecting the rights of plant breeders.
Personal Identification like identification cards, etc.
discussion. DNA fingerprinting has tremendous application especially in forensic sciences, which is mentioned in Table 2.
ETHICAL, LEGAL, AND SOCIAL CONCERNS
INVOLVING DNA FINGERPRINTING
The primary ethical, legal, and social issues concerning DNA
fingerprinting is privacy. DNA profiles are different from latent
fingerprints, which are useful only for identification. DNA can
provide insights into many aspects of a person and their families
including susceptibility to particular genetic disorders, legitimacy
of birth, and fertility. This increases the potential for genetic discrimination by government, society and others. Therefore, DNA
typing should be carried out in a very sophisticated way, and
should meet all the international standards and follow and abide
all the ethical, legal, and social concerns involved with DNA typing. Databanking also involves some ethical issues and requires
a balance between human rights and justice. Retention of samples for long periods of time is also risky, since this provides
considerable accessibility to private genetic information.
RELIABILITY OF DNA TECHNOLOGY
Generally, the legal system and courts have accepted the reliability of DNA testing everywhere, and admitted DNA test
results as evidence. However, DNA fingerprinting is still controversial because of some important aspects. One is the accuracy of the results, as result will always be in the form of some
probability value. Another aspect is the high cost associated
with analysis. Some of the other important aspects such as the
possibility of misuse of the technique, chances of manual error, and contamination cannot be ignored.
The accuracy of DNA fingerprinting has been challenged because DNA segments rather than complete DNA strands are analyzed, which may not be necessarily unique. More research
work is needed to confirm the uniqueness of DNA fingerprinting has not been conducted. In addition, DNA fingerprinting is
often performed in private laboratories that may not follow uniform testing standards and quality controls. Therefore, human
error could lead to false results. Awareness is still lacking about
this technology among law enforcing agencies and judiciaries,
requiring a lot of interaction between these and forensic scientists. DNA identification can be quite effective if used intelli-
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DNA FINGERPRINTING
gently. Portions of the DNA sequence that vary the most among
humans must be used; also, the number of loci studied should
be sufficient enough to make the results more reliable.
PROBLEMS WITH DNA FINGERPRINTING
DNA fingerprinting is not fully assured. The term DNA fingerprint is, in a true sense, a misnomer. We cannot compare it
with latent fingerprinting, as it is not as specific as fingerprints.
Actually, a VNTR pattern gives a probability value that the person in question is indeed the person to whom the VNTR pattern (of the child, the criminal evidence, or whatever else) belongs. The probability decides whether the person can be
reasonably matched with the DNA fingerprint.
1. Generation and determination of high probability is a requisite for forensic cases. The probability of a DNA fingerprint belonging to a specific person needs to be reasonably
high, particularly in criminal cases. High probability can be
achieved by increasing the number of polymorphic loci analyzed. Population structure can cause variation in allele frequencies between subpopulations (Lander and Budowle,
1994). VNTRs are not distributed evenly across all of human population. A given VNTR does not have a stable probability of occurrence, and not enough is known about the
VNTR frequency distributions among ethnic groups to determine accurate probabilities for individuals within those
groups. Some technical difficulties, like errors in the hybridization and probing process, will also affect the probability. Population studies should be carried out and reproducibility of the results should be confirmed.
2. DNA testing faces important problem of impurities of the sample. The sample collected from a crime scene most of the time
is mixed with soil and other potential contaminants and considerable time and effort in purification processes purification
on samples not directly amenable to analysis. Another important challenge to amplifying DNA samples from crime scenes
is the fact that the PCR amplification process can be affected
by inhibitors present in the samples themselves. The sensitivity of PCR with its ability to amplify low quantities of DNA
can be a problem if proper care is not taken. Mixed samples
can be challenging to detect and interpret. If mutation occurs
at the primer binding site it can result in failure to amplify,
which is known as null allele or allele dropout. Sometimes,
stutter bands are noted in the electropherogram of STR analysis, which is nothing but small peaks several bases smaller than
STR allele peaks, which occurs because of strand slippage.
These bands effect the interpretation of DNA profiles specially
in mixed samples, which requires good understanding of the
behavior of stutter products (John M. Butler, forensic DNA
typing). Proper training, better understanding, extensive experience, and careful analysis are required.
3. Very often investigators are not properly trained for sample
collection and encounter problems in identification and collection of proper DNA evidence from the scene of crime.
Contamination of the samples and using the correct sample,
proper labeling, etc., are a few important aspects, which
should be taken into consideration. The DNA laboratory
should follow the international standard and should be accredited.
4. Proper awareness about the subject is required among the
investigators, but unfortunately, interaction and proper communication is lacking between law enforcement agencies and
DNA laboratories.
5. Limited resources and poor infrastructure facility of different laboratories effects the efficiency of the DNA typing laboratories.
6. Risk of false or misleading results from DNA testing and
chances of tampering with the evidence cannot be ignored.
Strict confidentiality is required as far as identity of the sample is concerned, and each sample should be tested by more
than one examiner to confirm the results. Irrespective of having all these limitations, DNA fingerprinting is a very reliable
technique for identification if used efficiently and intelligently.
There are many international organizations, which are involved in quality control and uniformity of DNA fingerprinting such as the Technical Working Group on DNA Analysis
Methods, The DNA Advisory Board, National Institute of Standards and Technology in United States, and International Society for Forensic Genetics in Europe.
SOME HIGH-PROFILE CASES SOLVED BY
DNA FINGERPRINTING
1.
2.
3.
4.
5.
Identification of the remains of the last Russian Czar.
O.J. Simpson case in Los Angeles.
Clinton-Lewinsky affair.
Thomas Jefferson-Sally Hemings affair.
Identification of the bodies in World Trade Center attack: A
mass disaster.
6. Assassination case of Sri Rajeev Gandhi, Prime Minister of
India.
CONCLUSION AND FUTURE DIRECTIONS
The power of DNA technology will be of immense help in
the future. The limitations of the technique have to be given serious thought. Forensic DNA testing will improve day by day,
and will be benefited with the outcome of the Human Genome
Project. Microarray-based analysis will be in much use for its
more reliability and fast analysis. This technology has the potential to review the cases, which were previously reported with
older methods. There is a real need for public awareness of the
new DNA technologies and their implications. For instance, the
collection of the correct sample and its proper preservation is
very crucial. Productive interactions are required between the
forensic scientists and the law enforcement and other investigators. It is necessary to make this technology more popular and
cost effective so as to enable even developing and undeveloped
third world countries to take advantage of the technology as well.
ACKNOWLEDGMENTS
My special thanks to all those authors whose names are not
quoted here because of space constraints, and those who have
made the information freely available on the internet. I am
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thankful to Dr. S. E. Hasnain and Dr. J. Nagaraju, for their constant support and encouragement. A draft of this manuscript
was significantly improved through consultation with Dr. T.
Ramasarma, Dr. Gayatri Ramakrishna, and the comments of the
anonymous reviewer, and I thank them for their valuable suggestions. I am also thankful to Dr. Mark A. Jobling, author, and
Dr. Tanita Casci, senior editor, Nature Reviews Genetics for
permitting me to take Figure 3 from the published paper.
REFERENCES
BARALLON, R. (1998). Species determination by analysis of the Cytochrome b gene. In Forensic DNA Profiling Protocols. P.J. Lincoln
and J. Thompson, ed. (Humana Press, Totowa, NJ).
BRANICKI, W., KUPIEC, T., and PAWLOWSKI, R. (2003).Validation of cytochrome b sequence analysis as a method of species identification. J. Forensic Sci. 48, 83–87.
BUDOWLE, B., BIEBER, F.R., and EISENBERG, A.J. (2005). Forensic aspects of mass disasters: Strategic considerations for DNA-based
human identification. Legal Med. 7, 230–243.
BUDOWLE, B., MORETTI, T.R., NIEZGODA, S.J., and BROWN,
B.L. (1998). Proceedings of the Second European Symposium on Human Identification. (Promega Corporation, Madison, WI), pp. 73–88.
BUTLER, J.M. (2001). Forensic DNA typing: Biology and technology
behind STR markers (Academic Press, New York).
BUTLER, J.M., BUEL, E., CRIVELLENTE, F., and MCCORD, B.R.
(2004). Forensic DNA typing by capillary electrophoresis using the
ABI Prism 310 and 3100 genetic analyzers for STR analysis. Electrophoresis 25, 1397–1412.
CAETANO-ANOLLES, G., BASSAM, B.J., and GRESSHOFF, P.M.
(1991). DNA amplification fingerprinting using very short arbitrary
oligonucleotide primers. Biotechnology (NY) 9, 553–557.
COOPER, M.L. (2000). RAPD analysis of southern brown bandicoots
(Isodon obesulus) populations in West Australia reveals genetic differentiation elated to environmental variables. Mol. Ecol. 9, 469–479.
DIXON, L.A., MURRAY, C.M., ARCHER, E.J., DOBBINS, A.F.,
KOUMBI, P., and GILL, P. (2005). Validation of a 21-locus autosomal SNP multiplex for forensic identification purposes. Forensic
Sci. Int. 154, 62–77.
EDWARDS, A., CIVITELLO, A., HAMMOND, H.A., and CASKEY,
C.T. (1991). DNA typing & genetic mapping with trimeric &
tetremeric tandem repeats. Am. J. Hum. Genet. 49, 746–756.
HOYLE, R. (1998). Forensics. The FBI’s national DNA database. Nat.
Biotechnol. 16, 987.
JEFFREYS, A.J., WILSON, V., and THEIN, S.L. (1985). Individual
specific “fingerprints” of human DNA. Nature 316, 76–79.
JOBLING, M.A., and GILL, P. (2004). Encoded evidence: DNA in
forensic analysis. Nat. Rev. 5, 739–751.
KAYSER, M., et al. (2004). A comprehensive survey of human Y chromosomal microsatellite. Am. J. Hum. Genet. 74, 1183–1197.
LALJI S. (1991). DNA profiling and its applications. Curr. Sci. 60,
580–585.
KUMAR, L.D., KATHIRVEL, M., RAO, G.V., and NAGARAJU, J.
2001. DNA profiling of disputed chilli samples (Capsicus annum)
using ISSR-PCR and FISSR-PCR marker assays. Forensic Sci. Int.
116, 63–68.
LANDER, E.S., and BUDOWLE, B. (1994). DNA Fingerprinting dispute laid to rest. Nature 371, 735–738.
LANDSTEINER, K. (1901). Uber agglutinationserscheinungen normalen menschlichen blutes. Wien Klin Wschr. 14, 1132–1134.
LINACRE, A., and GRAHAM, D. (2002). Role of molecular diagnostics in forensic science. Expert Rev. Mol. Diagn. 2, 346–353.
MARTIN, P.D., HERMANN, S., and SCHNEIDER, P.M. (2001). A
brief history of the formation of DNA database in forensic science
within Europe. Forensic Sci. Int. 119, 225–231.
PARSOH, W., STEINLECHNER, M., SCHEITHAUER, R., and
SCHNEIDER, D.M. (1998). National DNA intelligence database in
Europe—Report on the current situation. In Proc 9th Symp Human
identification (Promega Corporation, Madison, WI). pp. 52–54.
PEEREN BOOM, E. (1998). Central DNA database created in Germany. Nat. Biotechnol. 16, 510–511.
SAIKI, R.K., BUGAWAN, T.L., HORN, G.T., MULLIS, K.B., and
ERLICH, H.A. (1986). Analysis of enzymetically amplified -globin and HLA-DQ DNA with allele–specific oligonucleotide probes.
Nature 324, 163–166.
SCHNEIDER, P.M. (1998). DNA databases for offender identification
in Europe—The need for technical, legal & political harmonization.
In Proc Europ 2nd Symp Human identification (Promega Corporation, Madison, WI) pp. 40–44.
VARSHA, et al. (1999). D1S80 variation in random Indian populations. Proceedings of X Intl. Symposium of Human Identification, FL,
USA.
VARSHA, et al. (2003). Identification of cooked meat sample by 12SrRNA sequence analysis. Proceedings of 55th annual meeting of
American Academy of Forensic Sciences, Chicago, IL.
WALLACE, D.C. (1999). Mitochondrial diseases in man and mouse.
Science 283, 1482–1488.
WEBER, J.L., and MAY, P.E. (1989). Abundant class of human DNA
polymorphisms which can be typed using polymerase chain reaction.
Am. J. Hum. Genet. 44, 388–396.
WEISING, K., NYMBOM, H., WOLFF, K., and MAYER, W. (1995).
DNA Fingerprinting in Plants and Fungi (CRL Press, Boco Raton,
FL).
WERRET, D.J. (1997). The National DNA database. Forensic Sci. Int.
88, 33–42.
WERRET, D.J., and SPARKES, R. (1998). Proceedings of Ninth International Symposium on Human Identification (Promega Corporation, Madison, WI) pp. 55–62.
WONG, Z., WILSON, V., PATEL, I., POVEY, S., JEFFREYS, A.J.
(1987). Characterization of a panel of highly variable mini-satellites,
cloned from human DNA. Ann. Hum. Genet. 51, 269–288.
ZEHNER, R., ZIMMERMAN, S., and MEBS, D. (1998). RFLP and sequence analysis of the cytochrome b gene of selected animals and man:
Methodology and forensic application. Int. J. Legal Med. 111,
323–327.
ZIEGLE, J.S., SU, Y., CORCORAN, K.P., NIE, L., MAYRAND, P.E.,
HOFF, L.B., MCBRIDE, L.J., KRONICK, M.N., and DIEHL, S.R.
(1992). Ligase-based detection of monoclonal repeat sequences. Genomics 14, 1026–1031.
Address reprint requests to:
Varsha
Laboratory of DNA Fingerprinting Services
Centre for DNA Fingerprinting and Diagnostics
ECIL Road
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E-mail: [email protected]
Received for publication November 4, 2005; received in revised
form December 14, 2005; accepted December 15, 2005.