Open Access Research Article
ROLE OF DNA IN CRIMINAL INVESTIGATION (By- Neeru Thakur)
Published Paper
Article Details
ROLE OF DNA IN CRIMINAL INVESTIGATION
Authored By- Neeru Thakur,
Research Scholar,
CT University, Ludhiana, Punjab.
Prof. (Dr.)
Simranjeet Kaur Gill, Principal,
School of Law, CT University, Ludhiana,
Punjab .
Abstract
DNA evidence
rarely the sole basis of
a prosecution case . It
is the most
useful when placed
alongside other evidence
such as fingerprints , footprints , crime scene
examination and eyewitness
accounts . Other biological evidence
may also be
collected , for example blood
splash patterns and microbial
information which may
give clues as
to the time
of the death . Every
person has a
unique DNA profile , making it
very useful for
identifying people involved
in a crime . Forensic scientists
can use DNA profiles
to identify criminals
or determine parentage . This paper
is an attempt
to reflect the
necessity of DNA profiling
during the scientific or
forensic investigation. A DNA
profile is like
a genetic fingerprint .
Deoxyribose Nucleic Acid
(DNA) is an
organic compound which
have a molecular
structure and found
in all prokaryotic
cell ( lack of
nuclear membrane around
nucleus ) and eukaryotic
cell ( true cell
with nuclear membrane ) . DNA is
a long polymer
of deoxyribose nucleotide . According to the number
of nucleotides and
base pair (bp) , we can
determine the length
of DNA . for example
: In Bacteriophage has
5386 nucleotide (Single
strand of DNA) , haploid human
cell has 3.3*109
bp (double stranded ),
Escherichia coli has
4.6 * 106 bp (
double stranded ), and
diploid human cell
has 6.6 * 109 bp (double stranded ). The genetic
material in DNA
allows the identification of
the perpetrator by the processing
and the analysis
of biological evidence
transferred in the
crime scene . Through the
processing of DNA
from biological fluid
samples alongside DNA
statistical interpretation ,
the identification of
an individual can
be done. This
is done when
swabbing known profiles
from the scene
and through DNA
databases, such as
CODIS , which contains
reference profiles from
past offenders , can be
used to search for
the questioned profiles
when a known
profiles is not
available. Forensic DNA
testing has done
more than just
punishing the guilty
for the crimes
they have committed .
Additionally , This paper aims
that the successes
of utilizing DNA
as evidence in
court to prosecute the
guilty and exonerate
the innocent for
decades, DNA is repeatedly
sought by judges , attorneys and
detectives as primary
from a crime
scene .
KEY WORDS : DNA profiling , DNA evidence ,
biological evidence , crime scene
examination , identification
of individual , DNA utilization .
Introduction
DNA is
a long polymer
of deoxyribonucleotides . RNA
was the first
genetic material . It is
used to act as
a genetic material
as well as
a catalyst but , RNA
being a catalysts was
reactive and hence
unstable. Therefore , DNA has
evolved from RNA
with chemical modifications
that make it
more stable. DNA
being double stranded and
having complementary strand
further resists changes
by evolving a
process of repair.1 The
presence of thymine
at the place
of Uracil also
confers additional stability
to DNA . DNA however
is dependent on
RNA but DNA being more
stable is preferred
for storage of
genetic information . 2 This genetic
information play a very vital
role in investigation
to identify the
criminals , bodies ,
parentage of individual . A cell
(functional and structural
unit of life) have
nucleus which have
chromosome and that
chromosome have DNA . DNA
is present in
nucleus as well
as in some
cell organelle like
plastid and mitochondria . DNA is
in mitochondria , so we
called it as (mt DNA) mitochondrial DNA.
There are around
16,000 bp of
mt DNA in human.
Importance Of Study
DNA can
be used to
identify criminals with
incredible accuracy when
biological evidence exists . In
cases where a
suspect is identified , a sample
of that person’s
DNA can be
compared to evidence from
the crime scene . The
result of this
comparison may help
to establish whether the
suspects has committed
the crime. But, In cases
where a suspect
has not identified , biological evidence
from the crime
scene can be
analyzed and compared
to offender profiles
in DNA databases
to help identify
the perpetrator . In all, DNA
technology is increasingly
vital to ensuring
accuracy and fairness
in the criminal
justice system.3
Objectives Of The Study
1. To
understand the structure
and functions of
DNA.
2. To
diagnose genetic disorders
and formulate new
drugs .
3. To
describe and explain
the ways that
DNA technologies can
be used in
criminal
investigation and turned
into DNA evidence
in criminal proceedings .
4. To
study the social
implications and transformations of cultures and
professional practices arising
from the presence
of DNA technology
in the criminal
justice system.
5. To
recognize and identify
the potential risks
arising from the
use of DNA
technology.
Research Methodology
The study
is based upon
the doctrinal research
method . The doctrinal study
will include study
of secondary data
which includes text
books , legal journals , statutes
, reports , judgments , newspaper , website , digests and
published statistics .
History Of DNA
DNA as
an acidic substance
present in nucleus
was first identified
by Friedrich Meischer
in 1869 . He named it as
NUCLEIN . however , due to technical
limitation in isolating
such a long
polymer intact , the elucidation
of structure of DNA remained
elusive for a very long
period of time . It
was only in
1953 that James
Watson and Francis
Crick , proposed a very
simple but famous
DOUBLE HELIX model
for the structure
of DNA . One of
the hallmarks of
their proposition was
base pairing between
the two strands
of polynucleotide chains .
however , this proposition was
also based on
the observation of
Erwin Chargaff that
for a double
stranded DNA , the ratio
between ADENINE , THYMINE ,
GUANINE and CYTOSINE
are constant and
equals one .4
Salient feature
of the Double
Helix structure of
DNA are as
follows :
1.
It is
made of polynucleotide chains , where the backbone is
constituted by sugar
phosphate , and the bases
project inside .
2. The
two chains have
anti-parallel polarity . It means , if
one chain has
the polarity 5’>3’ , the other
has 3’>5’.
3. The
bases in two
strands are paired
through hydrogen bond
(H-Bond) forming base
pair. Adenine forms
two hydrogen bonds
with Thymine from
opposite strand and
vice-versa . Similarly , Guanine
is bonded with
cytosine with three
H-Bonds . As a result , always a
purine comes opposite
to a pyrimidine .
This generates approximately
uniform distance between
the two strands
of the helix .
4. The
plane of one
base pair stacks
over the other
in double helix . This , in addition
to H-Bonds , confers stability
of the helical
structure .
So , the proposition
of a double
helix structure for
DNA and its
implication became revolutionary . very soon , Francis Crick
proposed the central
dogma in molecular
biology , which states that
the genetic information
flows from DNA
to RNA to
PROTEIN .5
Genetic Material Is DNA
The
unequivocal proof that
DNA is the
genetic material came
from the experiments
of Alfred Hershey
and Chase in 1952. They
worked with viruses
that infect bacteria
called bacteriophages . Bacteriophage
attaches to the
bacteria and its
genetic material then
enters the bacterial
cell . The bacterial cell treats
the viral genetic
material as if
it was its
own and subsequently
manufactures more protein
or DNA from
the virus that
entered the bacteria . They grew
some viruses on
a medium that
contained radioactive phosphorus
and some other
on medium that
contain radioactive sulfur . Viruses grown
in the presence
of radioactive phosphorus
contained radioactive DNA
but not radioactive
protein . Similarly , viruses
grown on radioactive
sulfur contained radioactive
protein but not
radioactive DNA because
DNA contain phosphorus
but does not
contain sulfur . Radioactive phages
were allowed to attach
to E-coli bacteria. Then ,
as the
infection proceeded the
viral coats were
removed from the
bacteria by agitating
them in a
blender . The virus particles
were separated from the
bacteria by spinning
them in a
centrifuge . Bacteria which was
infected with viruses
that had radioactive
DNA were radioactive , indicating that
DNA was the
material that passed
from the virus
to the bacteria
and protein did
nor enter the
bacteria from the
viruses . DNA is therefore
the genetic material
that is passed
from virus to
bacteria .6
DNA Testing Procedures
The DNA testing
process is comprised
of four main
steps :
Extraction :- DNA is located
within the nucleus
of cells throughout
the body and
the extraction step
is responsible for
breaking open the
nucleus and releasing
the DNA molecules
into solution .
Quantitation :-
To ensure
that the DNA
recovered from an
extraction is human
rather than from
another source such
as bacteria is
done through quantitation
where the quality
of DNA present in
a sample is
measured and assessed .
Amplification :-
DNA amplification
is accomplished through
the use of
a technique known
as polymerase chain
reaction (PCR). PCR
is a process
in which millions
of copies of
a specific sequence
of DNA can
be made in
a matter of
only a few
hours . This is
important for forensic
DNA samples since
the DNA often
found at crime
scenes is limited
in both quantity
and quality .7
Analyzation :- After
the PCR reaction
is completed it
results in a
large mixture of
amplified DNA molecules
which need to
be separated in
order to distinguish
the various molecules
from one another .
DNA Fingerprinting
DNA
fingerprinting is also
called DNA profiling
or forensic genetics ,
a technique employed
by forensic scientists
to assist in
the identification of
individuals or samples
by their respective
DNA profiles . It
is a chemical
test that shows
the genetic makeup
of a person
or other living
things . DNA fingerprinting involves
identifying differences in
some specific region
in DNA sequence
called as repetitive
DNA , because in these
sequences , a small stretch
of DNA is
repeated many times . These
repetitive DNA are
separated from bulk
genomic DNA as
different peaks during
density gradient centrifugation . The bulk
DNA forms a
major peak and
the other small
peaks are referred
to as satellite
DNA . Depending on base
composition , length of segment,
and number of
repetitive units , the satellite
DNA is classified
into many categories
such as micro-satellites , mini-satellites etc. These
sequences show high
degree of polymorphism
and form the
basis of DNA
fingerprinting . DNA
fingerprinting is the
basis of paternity
testing , in case of
disputes .8 99.9
% of
base sequence among
humans is same .
Sources of DNA
fingerprinting :
-
Blood ,
blood stain
-
Hair follicle
-
Skin
, Bone
-
Sperm
-
Saliva
, Sweat
Explanation (a)
of section 53
of CRPC, 1973 - examination shall
include the examination
of blood , blood
stains , semen , swabs in case
of sexual offences , sputum and
sweat , hair samples and
finger nail clippings
by the use
of modern and
scientific techniques including
DNA profiling and
such other tests
which the registered
medical practitioner thinks
necessary in a
particular case .9
Techniques Of
DNA Fingerprinting :
Techniques
of fingerprinting was
initially developed by
ALEC JEFFEREYS . He used a satellite
DNA as probe
that shows very
high degree of
polymorphism . It was called
Variable Number of Tandem (VNTR) .
The technique , as used
earlier , involved southern blot
hybridization using radiolabelled
VNTR as a
probe . It includes :-
i.
Isolation of DNA.
ii. Digestion
of DNA by
restriction endonucleases.
iii. Separation
of DNA fragments
by electrophoresis.
iv.Transferring of
separated DNA fragments
to synthetic membranes
such as nitrocellulose or
nylon.
v.
Hybridization using labelled
VNTR probe.
vi. Detection
of hybridized DNA
fragments by autoradiography . A schematic representation of
DNA fingerprinting .
consequently , DNA
from a single
cell is enough
to perform DNA
fingerprinting analysis. In addition
to application in
forensic science it has
wider application , such as
in determining population
and genetic diversities .
Role Of DNA Testing In
Criminal Investigation
Since it was
invented in 1984 , DNA
fingerprinting most often has
been used in
court cases and
legal matters . It can :
. Physically
connect a piece of
evidence to a
person or rule
out someone as
a suspect.
. Show the parentage
, sibling and other
relatives may be .
. Identify
a dead body
that’s too old or
damaged to be
recognizable .
. DNA
fingerprinting is extremely
accurate and reliable . The police
keep copies of
actual fingerprints.
. To look for
cures for disease.
. To
identify perpetrators and
exonerate innocent parties.
. All body tissue
contains DNA so, it
is unaffected by
outside contaminants such
as acids , bases or
other chemicals , a person
cannot alter the
results of their
DNA testing.10
Legal Admissibility
The
admissibility of the
DNA evidence before
the court always
depends on its
accurate and proper
collection, preservation and documentation
which can satisfy
the court that
the evidence which
has been put
in front, it
is reliable . But the
introduction of DNA
testing posed many challenges as
to constitutional validity
and evidential value
of such test .
The
constitutional validity can
be challenged on
the basis of
Article 20(3) and Article
21 of Indian
Constitution which provides
that “No person
accused of an
offence shall be compelled
to be a
witness against oneself.”
And “Right to
privacy.” In State of
Bombay v. kathikalu11 It
was held by
the Hon’ble court
that giving information
for forensic examination
is just like
providing relevant facts
within the meaning
of sections 9&11
of Evidence Act
and it does
not fall under
the parameter of
evidence against oneself .
In Asit Kapoor
v. union of
India12 It
was held that
no party to a
legal proceeding can
be compelled for
any scientific test
against his or
her will as it has
effect of infringing
upon his Right
to Privacy . some
important guidelines are
issued in Gautam
Khundu v. State
of West Bengal13 which
is summed up
as follows :
-
Matrimonial
court has power
to order a
person to undergo
some medical test.
-
Such order
wouldn’t be considered
as violation of
Right to personal
liberty enshrined under
Article 21 of Indian
constitution .
-
Such a
power is exercise
by court when
there is strong
prima facie case
and sufficient material
before the court . If
the respondent refuses
to medical examination
despite of the
order of the
court , then court will be
entitled to draw
adverse inference against
him .
While
testing the validity
of DNA tests
on the anvil
of Article 20(3)
of the Constitution
of India, the
Hon’ble Supreme Court
made following observation
in Selvi v.
State of Karnataka14 as :
The
matching of DNA
samples is emerging
as a vital
tool for linking
suspects to specific
criminal acts . It may
also be recalled
that as per
the majority decision
in Kathikalu case ,
the use of
material samples such
as fingerprints for
the purpose of
comparison and identification does
not amount to
a testimonial act
for the purpose
of Article 20(3) .
hence , the taking and
retention of DNA
samples which are
in nature of
physical evidence does
not face constitutional hurdles
in the Indian
context .
The Evidential value
of the forensic
information obtained from
the Experts under
section 45 of
Evidence Act,1872, is
not conclusive proof
but it can
be used as corroborative evidence . A
general rule is
that opinion of
a person having
special skill or
knowledge in a
particular field shall
be admissible to
the court of
law. Thus , the experts
assists and determine
fact in issue
and relevant fact
to furnish information
to judicial officers . 15 In Madan
Gopal Kakkad v.
Naval Dubey16 it
was held that
opinion of expert
is admissible . In Machindra
v. Sajjan Galpha
Rankhamba17 has
observed that an
expert opinion should
be demonstrative and
supported by convensing reasons.
In case Rohit
Shekhar v. N.D.Tiwari18 ,
in this case
Rohit Shekhar has
claimed to be the biological
son of N.D.Tiwari
and request for
DNA test but N.D.Tiwari
reluctant to undergo
such test stating
that it would
be the violation
of his Right
to Privacy and
would cause him
public humiliation . But supreme
court rejected this
point stating that
when the result
of the test
would not be
revealed to anyone
and it would
under a sealed
envelope, there is no
point of getting
humiliating . Supreme court ordering
congress leader N.D.Tiwari
to undergo the
DNA test is
very important from
the viewpoint of
the admissibility of
such evidence .
At present in
India there is
no concrete law
to govern issues
of admissibility of
forensic techniques . Some
Section i.e. sections
53 , 53(A) , 54 , 164 (A) of Code
of Criminal Procedure
govern science and
technology issue to
certain extend . Indian Judiciary
had adopted forensic
evidence but it
is legislative machinery
which is lagging
behind in assimilating
scientific development which
plays important role
not only to
solve high profiles
cases but rape
case and post-conviction matter
also . Therefore , it is completely
left on judicial
discretion either to
permit DNA test
or to deny
such request .
Drawbacks Of DNA Testing
1. The
process itself is
complex and tedious
and can give results that
may be hard
to interpret .
2. There is
no specific provisions
to govern forensic
science and techniques .
3.
Improper testing methods
may create false
positive or false
negative results .
4. In some
cases , authorities may force
certain individuals ,
innocent and otherwise
to undergo DNA
profiling as a
part of their data gathering.
It can be
violation of one’s
privacy. 19
5.
Matching DNA from
a crime scene
to DNA taken
from a suspect
is not an
absolute guarantee of
the suspect’s guilt .
Suggestions
-
Legislators should
take necessary step
to legislate a
uniform and national
level law on
conducting DNA tests
and admissibility in
courts .
-
To regulate procedure
in forensic laboratories
to increase reliability
on its report .
Labs should adhere
to high quality
standard , use of splitting
methods and uniform
standard for DNA
testing be adopted .
-
DNA samples
should be collected
from suspect only
after prior approval
of a Judge
or Magistrate .
-
A national
commission be created
to regulate and
monitor DNA profiling
labs .
-
Proper training
and sensitization of
legal fraternity is
required so as to overcome
contamination issues .
-
Process
and acceptability to
post conviction DNA
testing be incorporate
in Indian laws . So, proper chain
of custody should
be maintained .
Conclusion
DNA
technology is very
powerful investigative tools . DNA
has been used
in forensic science
to link the
evidence to the
suspect and for
identification of individual
and species . Both human
and non-human DNA
analysis has been
reported to aid
criminal investigation . DNA evidence
not only links
the suspect with
the crime but
also help exclude
the innocent . It can
be used to
identify missing persons
and victims in
mass disasters when
there is a
lack of positive
identification methods . In addition , DNA provides
information on kinship
relation i.e. material lineage
and paternal lineage
of people who
have different surnames . In
non-human , DNA plays important
role in species
identification such as
in wildlife crimes , narcotic plants , microbes , domestic animals
and food authentication. It
can also provide
linkage of samples
to an organism . However , there are
some limits to
DNA analysis of
forensic samples but miniaturization of
instrumentation was developed
to support on
site analysis as
well as high
throughput to perform
analysis of large
numbers of samples
in the labs .20 The emerging
technology will enable
fast , reliable and low
cost DNA analysis
in future which
will enhance the role
of DNA technology
in criminal justice
system .
End Notes
1. Stephen c. Meyer, Signature in the
cell: DNA and the Evidence for Intelligent Design, Harper Collins
Publishers.
2. M.P.Tyagi & K.N.Bhatia, Elementary
Biology Textbook, New Ed.
Vol.2, Trueman Publication, 2023
4. NCERT Biology Textbook, Molecular
Basis of Inheritance- Chapter 6
5. James D. Watson, DNA: The Story of
The Genetic Revolution, Penguin, 22 Aug 2017
6. Supra Note 4
7. Forensic Science- DNA testing
Procedures Available at https://dps.mn.gov>bca
8. Supra Note 6
9. Section 53 of “ The Code of Criminal
Procedure,1973”
11. AIR 1961 SC 1808
12. AIR 2004 Del 2003
13. AIR 1993 SC 2295
14. AIR (2010)7 SCC 263
15. Section 45 of “ The Indian Evidence
Act, 1872”
16. AIR 1992 SCW 1480
17. (2013) Cr no.1794, DOJ- April 19,2017
18. 2011(121) DRJ 563
19. Available at https://greengarageblog.org>pros and cons of DNA fingerprinting
Article Information
ROLE OF DNA IN CRIMINAL INVESTIGATION (By- Neeru Thakur)
Authors: Neeru Thakur
- Journal IJLRA
- ISSN 2582-6433
- Published 2022/07/19
- Volume 2
- Issue 7
About Journal
International Journal for Legal Research and Analysis
- Abbreviation IJLRA
- ISSN 2582-6433
- Access Open Access
- License CC 4.0
All research articles published in International Journal for Legal Research and Analysis are open access and available to read, download and share, subject to proper citation of the original work.
Disclaimer: The opinions expressed in this publication are those of the authors and do not necessarily reflect the views of International Journal for Legal Research and Analysis.