Definition
Evidence derived from analysis of deoxyribonucleic acid (DNA) — the genetic material present in every human cell — used to identify individuals with high scientific certainty in criminal investigations, paternity disputes, and missing persons cases.
DNA evidence is admitted in Indian courts under Section 45 BSA (expert opinion) as the opinion of a DNA analyst skilled in molecular biology. DNA analysis can: (a) match blood, semen, saliva, or hair at a crime scene to a specific individual; (b) establish paternity or family relationships; (c) exclude or include an accused as the source of biological material. The DNA Profiling Bill (DNAPB) has been proposed multiple times in India but has not yet been enacted as a comprehensive framework law. Courts have admitted DNA evidence in hundreds of cases — the Supreme Court in several decisions has treated DNA evidence as highly reliable but not conclusive on its own.
Statutory Definition
No standalone DNA evidence statute in India (the DNA Technology (Use and Application) Regulation Bill, 2019 was introduced but not passed as of 2024). DNA evidence is admitted under: Section 45 BSA — expert opinion on scientific matters; Section 53 BNSS (formerly Section 53 CrPC) — examination of the accused by medical practitioner including collection of blood, saliva, and other biological materials for examination; Section 164A BNSS — medical examination of rape victims, with consent, including collection of DNA samples.
Etymology & Origin
DNA is an acronym for 'deoxyribonucleic acid' — the molecule that carries genetic information in all living organisms. 'Evidence' from Latin 'evidentia' (clarity, proof). DNA evidence is proof derived from the examination of this fundamental biological molecule.
Full Legal Analysis
DNA Evidence: The Gold Standard of Identification
DNA evidence has transformed criminal justice worldwide. A single human hair, a drop of blood, a trace of saliva — each contains the person’s unique genetic signature. When matched against a database or a suspect’s sample, DNA can establish identity with a probability so high (1 in billions) that it effectively amounts to certainty. In India, DNA has resolved hundreds of rape cases, murder investigations, and paternity disputes — and exonerated innocent persons wrongly convicted on eyewitness testimony.
Admissibility of DNA Evidence in Indian Courts
DNA evidence is admitted as expert scientific evidence under Section 45 BSA. The DNA analyst must appear in court and be available for cross-examination on: (a) the chain of custody of the biological sample — was it collected without contamination?; (b) the laboratory procedures — were proper protocols followed?; (c) the statistical interpretation — what is the probability that the match is coincidental?; and (d) the database against which the sample was matched. Courts look for the Locard exchange principle: every contact leaves a trace — but they also examine whether the trace evidence is genuine (not planted) and properly analysed.
Supreme Court on DNA Evidence
In Sharad Birdhichand Sarda v. State of Maharashtra (1984) 4 SCC 116 (a pre-DNA era case), the Court laid down the importance of scientific evidence in circumstantial cases. In more recent cases like Kiran Bala Devi v. State of Bihar (2005) and paternity cases, courts have relied on DNA as conclusive evidence of biological relationship. In rape cases with consistent, certified DNA analysis, courts have convicted on DNA plus the victim's testimony alone. However, the Supreme Court has cautioned that DNA evidence should not be used without ensuring the chain of custody is intact and the laboratory is accredited.
“DNA does not lie — but the handling of DNA can. The power of DNA evidence depends entirely on the integrity of the process from sample collection to laboratory analysis to court presentation. A clean chain of custody and accredited analysis produces near-certain evidence; a contaminated or carelessly handled sample produces nothing reliable at all.”
This Term in Indian Statutes
Bharatiya Nagarik Suraksha Sanhita, 2023, 2023
"When a person is arrested on a charge of committing an offence of such a nature and alleged to have been committed under such circumstances that there are reasonable grounds for believing that an examination of his person will afford evidence as to the commission of an offence, it shall be lawful for a registered medical practitioner, acting at the request of a police officer not below the rank of sub-inspector, and for any person acting in good faith in his aid and under his direction, to make such an examination of the person arrested as is reasonably necessary in order to ascertain the facts which may afford such evidence, and to use such force as is reasonably necessary for that purpose."
BNSS Section 53: medical examination of arrested person including biological samples for DNA analysis
