DNA Profiling and Justice System
Context:
In mid-June, the Madras High Court examined, in detail, the wisdom of relying on DNA evidence alone to establish guilt.
What is DNA Profiling?
- It’s a forensic technique that identifies individuals based on their unique DNA sequences.
- This process involves:
- Extracting DNA: Obtaining DNA from a biological sample (blood, saliva, hair, etc.).
- Analysing DNA: Examining specific regions of DNA that vary greatly between individuals.
- Creating a profile: Generating a unique pattern or code representing the DNA sequence.
- Comparing profiles: Matching the profile with other DNA samples for identification purposes.
How reliable is DNA?
- DNA profiling is complicated, and each sequential step involved in generating a profile can vary depending on the laboratory’s facilities.
- According to Manikanda Raj, head of forensic medicine and toxicology at Chengalpattu Medical College and Hospital, DNA analysis as a process is based on probability and, in that sense, cannot be considered conclusive evidence.
- There are definite pitfalls, particularly with sample contamination, delay in lifting or testing the sample, unviable samples, or when the samples themselves are switched.
In Pattu Rajan v. State of Tamil Nadu (2019), the judges noted that while DNA evidence is increasingly accurate, its probative value varies with each case and is not infallible; thus, the lack of DNA evidence alone cannot be used to draw adverse conclusions if other reliable evidence supports a party.
Usage in India:
- The DNA profiling method used today in India is based on polymerase chain reaction (PCR) and uses short tandem repeats (STR).
- DNA testing as evidence is not covered under Bharatiya Sakshya Adhiniyam (BSA) and Bharatiya Nagarik Suraksha Sanhita (BNSS).
- DNA Technology (Use and Application) Regulation Bill 2019 in India aimed to establish a framework for the collection and storage of DNA profiles to aid criminal investigations.
- The bill proposed establishing a National DNA Data Bank and Regional DNA Data Banks to store DNA profiles. These databases would maintain separate indices for crime scenes, suspects/undertrials, offenders, missing persons, and unidentified human remains.
- The bill allowed for the collection of DNA samples from convicts, offenders, suspects, undertrials, and missing persons, with some exceptions. Consent was required except for serious offences punishable by more than seven years imprisonment or death.
- The Criminal Procedure (Identification) Act, 2022, enacted in India, provides a legal framework for the collection, storage, and management of identifiable information from individuals involved in criminal cases.
- The Act empowers police and prison officers to collect these measurements from convicts, arrested individuals, and those detained under preventive detention laws.
- The National Crime Records Bureau (NCRB) is designated to manage the storage, processing, sharing, and destruction of these records, which can be preserved for up to 75 years.
Practices in Other Parts of the World:
- Countries like Austria, France, and Germany have made provisions in their legal system to store DNA records of criminals committing certain crimes.
- The Combined DNA Index System (CODIS) developed by the FBI (USA) is a widely used platform that employs short tandem repeat (STR) DNA markers. CODIS allows for comparing DNA profiles from crime scenes to those of convicted offenders and suspects.
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Polymerase Chain Reaction (PCR) Polymerase Chain Reaction (PCR) is a laboratory technique used to amplify a specific DNA sequence. It’s like making millions of copies of a tiny piece of DNA. This is essential for analysis, as often there is not enough DNA available for testing. Short Tandem Repeats (STRs) Short Tandem Repeats (STRs) are sections of DNA that contain repeated short sequences of nucleotides. The number of repeats varies between individuals, making them highly variable and useful for identification. |
