DNA
By
NOOR
ALAM KHAN
Advocate Supreme Court of Pakistan
&
Chairman, Voice of Prisoners
Member KPK Bar Council,
DNA VALUE
A DNA
(Deoxyribonucleic Acid test) test involves a detailed scrutiny of the DNA
composition of an individual, which is unique to that person. DNA is the
genetic make up of an individual and it is found in
every cell of the body. For example, it is in blood, saliva, skin and hair.
This protein is responsible for the genetic instructions required to create an
organism that reflects its own unique traits and the ones that are inherited
from the parents too. Everyone has DNA. A person inherits their DNA makeup from
their parents. Therefore, blood relatives share similar DNA.
People undergo
DNA testing for various reasons, some of which are geneological,
clinical, and legal purposes. A geneological DNA test
is usually meant lo trace the ancestry of an individual, and for comparing results to know the historical
and geographical origins. This test is usually for research purposes, especially
in population genetics. DNA testing compares genetic material from 2 or more
people to determine if they are biologically related. The genetic material for
testing is usually taken from a mouth swab or blood sample.
Hence, the
values of these tests vary as per the test performed and the intention for
which the test is being conducted. DNA tests happen to be the most accurate
when looking for specific results and can be very subjective if used for
aspects that require a broader perspective that goes beyond generations in
count.
EVIDENTIARY VALUE
DNA test
provided the courts a mean of identifying perpetrators with a high degree of
confidence. By using DNA technology the courts were in a better position to
reach at a conclusion whereby the real culprit would be convicted, potential
suspects would be excluded and wrongfully involved accused would be exonerated.[1]
First, DNA
evidence is presented in court through expert testimony. The witness must be
properly qualified as an expert. Second, the DNA evidence must pass the tests
of admissibility. Third, there are several recognized DNA testing methods. This
includes Polymerase Chain Reaction and Short Tandem Repeat.
Test would not
be conducive and the same would not serve any useful purpose except unnecessary
delay, multiplicity of litigation, which could create other complications. High
Court could not assume role of investigator to hold inquiry. DNA test by itself
could not set the matter at rest, when it was being opposed by contesting party
with right to produce its rebuttal. Such proceedings would tantamount to fresh
trial needing a factual inquiry, which was beyond the scope of constitutional
jurisdiction. There would be no certainty with such test report, when dead body
and grave might not be identifiable due to lapse of considerable period and
carrying out such test under grave doubts would create further complications
instead of resolving the matter. High Court therefore, declined to allow DNA
test.[2]
Utility and evidentiary value of DNA test is acceptable, but not in a case
falling under the penal provisions of zina punishable
under Hudood Laws having their own standard of proof.[3]
Forensic DNA
profiling has been under intense judicial scrutiny by the courts for over 2
years. Even so, an overwhelming majority of the courts have admitted forensic
DNA evidence after reviewing it under the varying standards traditionally
afforded novel scientific evidence. In doing so, the courts have recognized in
numerous decisions that genetic profiles developed from an individuals
DNA are reliable, probative, and objective.
However, despite
the many favorable decisions, DNA evidence, if challenged, must continue to
undergo a pre-trial review, at least until a court of appeals in the
jurisdiction in which the evidence is offered addresses the question of whether
DNA evidence is acceptable. At such hearings, challenges to the evidence place
at issue the ability of the forensic laboratories to match similar DNA profiles
reliably, and thereafter, the ability to assess the frequency that the matched
profile is expected to occur in the
ADMISSIBIUTY STANDARDS
Traditionally,
two standards have been used to admit novel scientific evidence in courts.
Specifically, courts have adopted either the "Frye standard" or the
"relevancy standard" when deciding whether novel scientific evidence,
such as DNA profiling, will be admitted for use in court.
JUDICIAL ACCEPTANCE
`Forensic DNA
profiling has been reviewed extensively by the courts under the varying
standards afforded novel scientific evidence, and the number of favorable
decisions is encouraging. An overwhelming majority of courts have admitted
forensic DNA profiling results from the three major laboratories involved in
forensic DNA analysis.
A very few
unreported trial court decisions have also rejected DNA profile evidence
offered in a criminal proceeding. These courts have rejected DNA evidence for
differing reasons, to include the existence of some dissent in the scientific
community over some aspects of the approach to population statistics and the
complexity of the evidence. However, the rulings that reject DNA evidence
because of some divergence in the scientific community are clearly not
consistent with the standards established by "Frye". Because
"Frye" requires only that the scientific technique be generally
accepted in the scientific community, some divergence in the scientific community
is expected. These isolated adverse decisions have not generally been followed
by other courts in the same jurisdictions that have admitted DNA evidence in
criminal trials. DNA test provided the courts a mean of identifying
perpetrators with a high degree of confidence—By using
DNA technology the courts were in a better position to reach at a conclusion
whereby the real culprit would be convicted, potential suspects would be
excluded and wrongfully involved accused would be exonerated. Administration of
DNA tests and preservation of DNA evidence should be made mandatory in rape
cases.
DEFENSE CHALLENGES TO ADMISSIBILITY
Major defense
challenges are mounting in duration and magnitude as defense attorneys seek to
counter the potential impact on the jury of forensic DNA profiling. These
challenges focus on bias, matching, and population statistics.
BIAS
Few defense
experts contend that the forensic test is biased against the suspect, since the
examiner is aware of which samples the contributor expects will match. However,
the fact is the FBI's DNA test results actually exclude the named suspects in
about one-third of the submitted cases, often when traditional serological
examinations had included the suspect as the potential source of the sample.
(32) These statistics are similar to those reported by other laboratories
performing forensic DNA analysis.
MATCHING
Experts for the
defense still challenge the ability of the forensic DNA laboratories to
determine reliably a match given the deteriorated or degraded condition of most
forensic samples. They contend that degraded samples cause the markers to shift
during the processing of the sample to an unknown degree, possibly resulting in
a false matching of samples. No court, however, has found these criticisms to
be valid. Now 1 would like to dilate upon the question of conducting the DNA
Test. DNA Test is not to be directed as a matter of routine in cases where the
father refuses to acknowledge his child born during lawful wedlock, for the
reason that otherwise the presumption under Articles 117, 118, 119 and 128 of Qanun-e-Shahadat Order, 1984 that
a child born during the continuance of a valid marriage and within two years
after its dissolution, provided the mother remaining unmarried during this
period, shall be conclusive proof that he is legitimate child of that man,
unless the man denies the same
POPULATION STATISTICS
The principle
focus of current attacks is on the population statistics reported by the
laboratory after a match has been established. Because the current application
of the technology does not yet exclude one profile from that of every other
person in the world, DNA profiling laboratories sample a portion of the
population to determine how common or rare certain DNA profiles occur in the
population. From these data, the laboratory then develops a statistical
estimate of how frequently a particular DNA profile is likely to appear in the
Few scientists
have testified that the FBI has not sufficiently addressed the differences
among ethnic subpopulations within a race, and therefore, cannot properly
assess the resultant effect upon the statistical calculations provided for a
match. However, only two trial courts have accepted the opinions of these
experts in FBI Laboratory cases as representative of any significant part of
the scientific community, and therefore, rejected the population data estimates
provided by the FBI. (33)
However, this
objection is not expected to persist. The great majority of
courts reviewing DNA profiling evidence under the differing standards of review
have considered the challenges to forensic DNA profiling and now
recognize the technique as reliable and generally accepted by the scientific
community. Moreover, the scientific community and the FBI Laboratory have
developed and continue to develop data that are directly responsive to the
issues raised in the pre-trial hearings.
This information
continues to be disseminated to the appropriate community of scientists. As
this information is disseminated more fully, the consensus of the community
should be manifestly more apparent in favor of the FBI Laboratory's
conservative use of population statistics in DNA profiling.
INVESTIGATIVE CONSIDERATIONS
While DNA
profiling is fast gaining acceptance by the courts, investigators should be that
forensic DNA evidence does not yet positively identify the depositor of a
biological sample. It is but one factor of identification and cannot be relied
upon alone to support a determination of innocence or guilt.
Given the
current state of the technology, forensic DNA analysis is limited to
determining whether the known biological sample from an individual is
genetically similar to a questioned biological sample. Moreover, the relevance
of a match or an exclusion varies depending on the
circumstances in each case
Also,
investigators must be aware of the limitations of DNA analysis that will impact
on the decision of whether a person should be excluded as a suspect in the
crime. For example, a woman is raped, and some semen is recovered. But, suppose
the DNA profile of the semen recovered does not match the DNA profile of the
suspect. Is the suspect exonerated? Perhaps not.
Consider, for
example, that the victim may have had recent, consensual sexual relations with
her husband or a boyfriend before the rape occurred. The husband or boyfriend
of the victim may be the sole contributor of the sample taken from the victim
immediately after the rape, if the person responsible for the rape did not
contribute a semen sample of evidentiary value. Consequently, the forensic DNA
profile will not match the suspect's profile, but the absence of the suspect's
DNA does not exclude the suspect.
Accordingly,
when additional (non-DNA) evidence gives the investigator cause to believe that
a particular suspect is responsible for the crime, despite the DNA test results
that suggest the exclusion of the suspect, it is essential for the investigator
to determine whether the victim had consensualsexual
relations before the rape occurred. If so, a DNA sample should be obtained from
that person for comparison to the forensic sample.
Samples taking
technique in
A match between
the forensic profile and the husband's and/or boyfriend's profile indicates
only that the DNA of the person believed responsible for the crime was not
recovered from the victim. It follows that the principal suspect cannot be
exonerated as the one who committed the crime on the basis of the DNA test
results.
Best possible
evidence in the case in order to find out the truth or falsity of the
allegation without loss of time would he the DNA test. Need for scientific
verification through blood/semen grouping had been repeatedly expressed by
superior judiciary, particularly in rape cases. Prosecution agencies should
take heed and use latest available technology to trace and locate the actual
criminal. DNA finger printing was a successful clincher. Under
Art. 164 of Qanun-e-Shahadat,
1984, Court might allow to be produced any evidence available because of modern
devices or techniques. Holy Qur'an and Sunnah did not
forbid employing scientific or analytical methods in discovering the truth. On
the contrary the discovery and investigation had been strongly recommended by
the Holy Qur'an and Sunnah. Courts in matters
relating to Offence of Zina (Enforcement of Hudood) Ordinance, 1979 had all the powers to permit
reception of evidence including resort to DNA test, if demanded by the
occasion. Fundamental duty of the courts is to arrive at the truth without
depriving an affected party to establish its point of view.[5]
CONCLUSION
Deoxyribonucleic
acid, or DNA, is the fundamental building block for an individual's entire
genetic makeup. DNA is a powerful tool for law enforcement investigations
because each person's DNA is different from that of every other individual
(except for identical twins). With few exceptions, courts throughout the
nations have overwhelmingly admitted DNA test results, regardless of the
admissibility standard used by the particular jurisdiction. The RFLP
(Restriction Fragment Length Polymorphism) technique, along with other newly
emerging DNA technologies, has already begun to revolutionize personal
identification in criminal cases.
As the courts
continue to recognize the reliability and probative value of DNA evidence, the
public will benefit greatly from increased efficiency of criminal
investigations and trials. At some point in the not too distant future, DNA
evidence will be routinely admitted in criminal trials and will become as
common as the use of fingerprints. Moreover, advances in technology will allow
for unique identification of suspects based on .their genetic profiles, putting
to rest entirely many of the criticisms based on the limitations of the current
technology.