DNA PROFILING (DEOXYRIBONUCLEIC ACID TYPING)

General-

Life on earth is based on cells; Cell is the basic unit of life. There are around trillions of cells in a human blood. Every cell has a nucleus (except the RBCS); Inside the nucleus which is considered to be the central processing unit of the cell, 23 pairs of chro-mosomes are present. Twenty-two pairs of autosomal chromosomes and one pair of sex chromosomes (XX in females and XY in males). Chromosomes carry linearly arranged genetic units, which are materially referred as Deoxyribonucleic Acid (DNA). There are about 3 billion nucleotides in human DNA. Human DNA is approximately 2 metres long if it is place end to end from 46 chromosomes of a single cell. DNA is present in coiled and super coiled form in the cell. The super coiled structures are known as the chromosomes. This DNA contains genetic information which decides the phenotypic character (height, skin colour, eye colour, hair colour, etc) of an individual. The DNA carries the genetic information from parents to offspring, being half of the DNA from mother and the other half from father. The DNA carries all the information to make proteins (hormones, antibodies, enzymes and structural proteins like actin, myosin, keratin, tubuline) for proper functioning of the body. Another class of DNA present in human cell is the mitochondrial DNA which is present in the cell organelle mitochondria. Unlike nuclear DNA mitochondrial DNA is maternally inherited because the mitochondria of sperm are present in the tail and the tails is digested by hyluronic acid present around the egg cell at the time of fertilisation. The DNA is the genetic material that makes every individual different, except for genetically identical twins. A pattern of chemical signals ie, genetic code, has been discovered within the DNA molecule, which is very unique to each individual, just like their actual fingerprint. Thus, the DNA profiling, unique to each individual, is colloquially referred to as 'DNA Fingerprinting' and it is also known as DNA typing. The companies who offer the DNA profiling claim that a DNA match of two individuals is as unlikely as 1 in 30 billion. One more estimation puts it at 1 in 800, 000, 000 The chemical DNA was first discovered in 1869, but its role in genetic inheritance was not demonstrated until 1943. In 1944, Oswald Avery made the breakthrough discovery that DNA is the basic genetic material. A few years later, in 1953, James Watson and Francis Crick determined that the structure of DNA is a double-helix polymer, a spiral consisting of two DNA strands wound around each other. The technique of DNA Fingerprinting was 229 first developed in 1984 by Dr Alec Jeffreys from Britain. Since then, increasing attention has been paid around the world to the use of DNA profiling for individualisation purposes in criminal and allied cases. Paternity testing is another important use through DNA since 1988. The use of Restriction Fragment Length Polymorphism (RFLP) analysis of minisatellites or Variable Number of Tandem Repeat (VNTR) loci scattered along the chromosomes has spread interest among the medico legal professionals. The use of microsatellites or Short Tandem Repeats (STRs) also gained momentum with the passing years. These are consecutive repeats that are abundantly found in DNA. In contrast to 100-200 bps length of RFLPS and VNTRs, the STRS are of a smaller length of 2-10 bps. The short size of STRS is particularly useful if the sample is degraded or with Low Copy Number (LCN) DNA. Such degraded or fragmented DNA is encountered in samples that have been exposed to hostile external environment conditions like sunlight, heat, excessive salt etc. The traditional techniques like RFLP and VNTRS are not very helpful in such cases. The variants of STRS including Autosomal STR, MINI-STR, Y-STR and X-STR have immensely contributed to the forensic field. Three types of results are possible after comparing the question sample (Q) and the known sample (K) in cases of autosomal, Y and X STR markers analysis. These are-(1) Exclusion This result is produced when the STR haplotypes are different and could not have originated from the same source. (2) Inclusion (or failure to exclude)- This result is produced when STR haplotypes that result from Q-K comparison are the same and could have originated from the same source. (3) Inconclusive:-The result is inconclusive when the data are insufficient to render an interpretation or in other words ,ambiguous results are obtained.

The Autosomal STR markers: are commonly used to establish identity and settle paternity disputes. They are studied on all the 22 pairs of autosomes to avoid linkage issues within the markers. …………………………..

Samples required for DNA profiling. Any biological material such as a drop of blood, saliva, semen, and any body part such as bones, tissue, skull, teeth, and hair with the root found at the scene of crime may serve as a sample for DNA profiling. The CDFD gives the following guidelines about collecting samples:

(i) Maternity/paternity/parentage: Blood samples of mother, disputed child and alleged father are required. The blood samples (2 - 3ml) can be collected in the sterile blood collection material (EDTA vials) sent by the laboratory, in the presence of Court authorities. These samples should be sent in ice in a thermos flask either by a messenger or through courier, so as to reach the laboratory within 72 hours after collection.

ii) Identity of the deceased: Any body part of the deceased found at the scene of crime along with the blood samples of the blood relatives of the suspected individuals (viz., parents, and children) should be sent.

(iii) Identity of rape/rapist: Blood / semen stained clothes, garments, swabs, and slides of the victim and the accused is forwarded to the laboratory. …………………………………………………………….

Problems linked with DNA profiling. One of the lasting effects of the OJ Simpson case will likely be greater scrutiny by defence lawyers of the prosecution's forensic DNA presented in criminal cases. In the Simpson case, the defence, in essence, put the crime evidence laboratory on trial. There is no substantial dispute about the underlying scientific principles in DNA profiling, however, the adequacy of laboratory procedures and the competence of the experts who testify should remain open to inquiry.

Although, there is a common consensus within the scientific community that DNA profiling can yield results with a very high probability, the complex procedure of DNA profiling is not without problems. At every phase of the seven-step procedure just described, mistakes and improper handling of the DNA-probe can produce false results which in some cases can lead to a life sentence or even death-penalty judgement. Therefore, the adequacy of laboratory procedures and the competence of the experts who testify should remain open to inquiry.

Furthermore, the DNA samples can be mixed up by the police or the laboratory personnel (this actually took place in one case) or the amount of DNA can be insufficient. The various contaminants include microbes, fibres, concrete, soil, vegetable matter, other body fluids besides foreign DNA from field agents and laboratory workers. It can be avoided by handling the forensic evidence at a place that is segregated from the , where amplication of the sample is to be conducted. If the sample is accidentally mixed with foreign DNA before amplification, the contaminant will also get amplified resulting in mixed profiles at the time of STR analysis. Secondly, a significant 'source of error' is the incomplete digestion of the DNA by the restriction enzymes. The other extreme can be an over-digestion also called 'star activity'. Thirdly, a 'band shift' can occur, meaning that the DNA fragments which are put in several lanes next to each other can influence each other's mobility, thus causing wrong results of the gel electrophoresis. In connection with the problem of 'band shift', the gel electrophoresis itself may not be conducted properly, i.e., the voltage can be too low or too high or the concentration of the gel can be incorrect. Finally, the expert who determines a match can be biased ”.

In our legal framework DNA evidence is evaluated on the strength of Articles 59 and 164 of the Qanun-e-Shahadat, 1984 (QSO). The former provision states that expert opinion on matters such as science and art falls within the ambit of 'relevant evidence'. On the other hand, the latter provision provides that the Court may allow reception of any evidence that may become available because of modern devices and techniques. Under this regime the technician who conducts experiment to scrutinize DNA evidence is regarded as an expert whose opinion is admissible in Court. Subsection (3) of Section 9 of the Punjab Forensic Science Agency Act, 2007, reaffirms this legal position when it enacts that "a person appointed in the Agency as an expert shall be deemed as an expert appointed under Section 510 of the Code [of Criminal Procedure, 1898] and a person specially skilled in a forensic material under Article 59 of the Qanun-e-Shahadat, 1984 (P.O. X of 1984)." A combined reading of all these provisions shows that the report of the Punjab Forensic Science Agency regarding DNA is per se admissible in evidence under Section 510, Cr.P.C. Nevertheless, it must be noted, there is no express provision like Article 128 of the Qanun-e-Shahadat Order foreclosing admissibility of evidence by articulating a conclusive presumption as in paternity disputes. Since DNA is reckoned as a form of expert evidence in criminal cases, it cannot be treated as primary evidence and can be relied upon only for purposes of corroboration. This implies that no case can be decided exclusively on its basis if there is no primary piece of evidence, like oral evidence. Credibility of the DNA test inter alia depends on the standards employed for collection and transmission of samples to the laboratory. Safe custody of the samples is pivotal. Thus, in every case the prosecution must establish that the chain of custody was unbroken, unsuspicious, indubitable, safe and secure. Any break in the said chain or lapse in the control of the sample would make the DNA test report unreliable. In The People v. O.J. Simpson the famous U.S. footballer was accused of slitting throat of his ex-wife Nicole Brown Simpson, and knifing to death her friend, Ronald Goldman. The prosecution's case was essentially based on DNA evidence but the Court rejected it when it was found that the Los Angeles Police Department had made serious mistakes in handling it.

It is settled principle of law that for giving benefit of doubt, it is not necessary that there should be so many circumstances rather if only a single circumstance, creating reasonable doubt in the mind of a prudent person, is available then such benefit is to be extended to an accused not as a matter of concession but as of right. The zeal to punish an offender even in derogation or violation of the law would blur the distinction between arbitrary decisions and lawful judgments. No doubt, duty of the courts is to administer justice; but this duty is to be performed in accordance with the law and not otherwise. The mandatory requirements of law cannot be ignored by labelling them as technicalities in pursuit of the subjective administration of justice. One guilty person should not be taken to task at the sacrifice of the very basis of a democratic and civilized society, i.e., the rule of law. Tolerating acquittal of some guilty whose guilt is not proved under the law is the price which the society is to pay for the protection of their invaluable constitutional right to be treated in accordance with the law. Otherwise, every person will have to bear peril of being dealt with under the personal whims of the persons sitting in executive or judicial offices, which they in their own wisdom and subjective assessment consider good for the society.

Criminal Appeal No. 102-J of 2018.
(Fayyaz Ahmad Vs. The State.)
Criminal Revision No. 38 of 2018.
(Zadan Bibi Vs. The State and another)