DNA: Gold Standard in Probes

Above: Forensic officials inspect  restaurant premises in Bengaluru after a fire killed five people/Photo: UNI

The passing of DNA Technology (Use and Application) Regulation Bill will help strengthen the justice delivery system and ensure that DNA tests are done in accredited labs and data is protected from misuse 

By Dr KK Aggarwal

In a farsighted move, the Lok Sabha recently passed the DNA Technology (Use and Application) Regulation Bill. This could strengthen the criminal justice delivery system and change the face of policing and medicine. The Bill was formulated recognising the need for regulation of DNA technology for establishing the identity of missing persons, victims, offenders, undertrials and unidentified deceased persons. DNA evidence is considered the gold standard in crime investigation.

In fact, one of the reasons that the judicial system often fails the litmus test of speedy justice and is straddled with a huge number of undertrial detenues languishing in jail, is the dreadful failure of the police and investigating agencies to adopt modern forensic methods.

DNA is made up of half the biological mother’s DNA and half the biological father’s DNA. Fifty percent of our DNA is passed down to our biological children. This ensures that each DNA is unique and allows for accurate testing of parentage and direct descendants through a paternity test. Only identical (monozygotic) twins share the same DNA profile. DNA evidence can include different tissues, teeth, bones, blood (a drop is enough), spit, semen detected on cloth using specific staining procedures and skin cells sloughed off with sweat.

The key components of this Bill include:

• Establishment of a DNA Regulatory Board: Among the various functions envisaged for the DNA Regulatory Board are advising governments on all issues relating to establishment of DNA laboratories and DNA databanks and granting accreditation to laboratories and to suspend or revoke such accreditation.
• The Board will also ensure that the information relating to DNA profiles, DNA samples and any records thereof, forwarded to or in custody of the National DNA Databank or the Regional DNA Databanks or a DNA laboratory or any other person or authority under this Act are secured and kept confidential.
• No laboratory shall undertake DNA testing, analysis or any other procedure to generate data and perform analysis relating thereto without obtaining accreditation from the Board.
• Establishment of a National DNA Databank and Regional DNA Databanks to assist in forensic investigations.
• All DNA labs are required to share DNA data prepared and maintained by it with the National DNA Databank and the Regional DNA Databanks.
• Every DNA Databank shall maintain the following indices for various categories of data: a crime scene index; a suspects index or undertrials index; an offenders index; a missing persons index and unknown deceased persons index.
• The Bill also provides for sharing of DNA profiles with foreign governments or international organisations.
• There is a provision of penalty for unlawful access to information in a DNA databank and also for destruction, alteration, contamination or tampering with biological evidence.

The Bill also allows the use of DNA technology for certain civil matters specified in the Schedule. These include parentage disputes, pedigree, immigration, assisted reproductive technologies and transplantation of human organs. In particular, the Schedule includes DNA testing for issues relating to establishment of individual identity. Currently, laboratories also carry out DNA testing for medical or research purposes. For example, diagnostic laboratories use DNA testing to check whether an individual may be diagnosed with a particular disease such as cancer or Alzheimer’s.

These instances of use or lack of use of DNA as evidence in crimes illustrate why we need this Bill.

• Delayed DNA report: Two decades back, a doctor was arrested and jailed on charges of murdering his wife. He was released only nine months later after it was proved that sperm found inside his deceased wife was not his.
• DNA tests help in tracing the accused:

A DNA match from a toothbrush left behind at a hideout by 26-year-old Parashuram Waghmore, accused of shooting journalist Gauri Lankesh on September 5, 2017, was among the key pieces of evidence found by the Karnataka SIT. His DNA profile was identical with the DNA profile result of epithelial cells detected on a toothbrush sent to the DNA section of the Karnataka Forensic Science Laboratory. Waghmore, a former activist of the Sri Ram Sena, was identified by the SIT as the man who shot Lankesh. The toothbrush was dumped by a suspect, building contractor HL Suresh, whose house was used as a hideout for planning and executing the Lankesh murder.

• Proving paternity: In 2008, Rohit Shekhar Tiwari filed a paternity suit claiming that Congress politician ND Tiwari was his biological father. The court ordered that DNA mapping of Tiwari be done. The test results, released by the court on July 27, 2012, established that Tiwari was the biological father of Rohit, and that Ujjwala Tiwari was the biological mother. After much furore, on May 14, 2014, ND Tiwari married Ujjwala in Lucknow.

The use of DNA has to be scientifically done. High-profile murder cases like Aarushi, Nirbhaya, Priyadarshini Mattoo and Jessica Lal clearly bring out existing issues in the criminal justice system, be it crime scene contamination, lack of DNA evidence, over-reliance on witnesses in court or on circumstantial evidence. Not only does this prolong the trial process, it also puts a lot of pressure on the police, forensic team, investigating authorities, lawyers and the judiciary, thus impacting the final verdict.

In the Aarushi-Hemraj double murder case, which remains unsolved, the CBI collected all circumstantial and “scientific” evidence to nail the accused, but did not go for the crucial Touch-DNA test as it was apparently expensive. Rajesh Talwar, the father of Aarushi and an accused in the case, had initially stressed the need for a Touch-DNA test to establish his innocence. Four overseas laboratories were approached by the CBI for the test. Only one UK-based lab agreed to develop DNA from the exhibits with the Low Copy Number technique. Due to the cost factor and ex­pert opinion that the method was not foolproof, it was felt by the CBI that it would be better to concentrate on the material at hand instead of embarking on a wild goose chase.

There are many types of DNA testing. Two procedures commonly used are the Restriction Fragment Length Polymorphism (RFLP) testing and Polymerase Chain Reaction (PCR) testing. RFLP testing usually requires larger amounts of DNA, and for proper results, the DNA sample must be uncontaminated. PCR testing, on the other hand, requires smaller amounts of the sample. But it is a highly sensitive test and the slightest contamination can alter or influence the results. The Touch-DNA method, on the other hand, requires very small samples such as skin cells left on an object after it has been touched or casually handled. Touch-DNA analysis only requires seven or eight cells from the outermost layer of the human skin. However, the false positive rate is high due to easy contamination of samples.

As DNA samples are highly contaminable, precautions should be taken while handling them such as wearing gloves, avoiding coughing, sneezing, and smoking, preventing direct sunlight or water on DNA samples, using proper bags for samples and maintaining conditions for storage of special samples.

DNA profiling has been in use in India for years and is a part of admissible expert evidence under Section 45 of the Evidence Act, 1872. But India conducts less than 10,000 DNA tests in a year compared to 60,000 in the UK. Unlike a handwriting expert’s opinion during a trial, which may or may not be accepted because it is still considered an art rather than a science, DNA profiling is more clear-cut and totally methodical.

In fact, the 271st Law Commission Report strongly recommended wider use of this method to strengthen the criminal justice system. However, collection of DNA evidence in appropriate cases must be in compliance with Article 21 of the Constitution which guarantees to every person the fundamental right to life and liberty.

In Dharam Deo Yadav vs State of Uttar Pradesh (2014), a judgment which deals with the admissibility of DNA evidence, the Supreme Court observed: “Crime scene has to be scientifically dealt with without any error. In criminal cases specifically based on circumstantial evidence, forensic science plays a pivotal role, which may assist in establishing the evidence of crime, identifying the suspect, ascertaining the guilt or innocence of the accused. One of the major activities of the investigating officer at the crime scene is to make thorough search for potential evidence that has probative value in the crime. Investigating officer may be guarded against potential contamination of physical evidence which can grow at the crime scene during collection, packing and forwarding. Proper precaution has to be taken to preserve evidence and against any attempt to tamper with the material or causing any contamination or damage.”

So while a Bill has been passed, there is much more that needs to be done to make DNA testing effective.

—The writer is President, Heart Care Foundation of India, and President-elect, Confederation of Medical Associations of Asia and Oceania