Science For Everyone: DNA Again

DNA is the abbreviation of Deoxyribo Nucleic Acid. It is the basic genetic material in all human body cells. It is not contained in red blood corpuscles. It is, however, present in white corpuscles. It carries the genetic code. DNA structure determines human character, behaviour and body characteristics. DNA profiles are encrypted sets of numbers that reflect a person’s DNA makeup which, in forensics, is used to identify human beings. DNA is a complex molecule. It has a double helix structure which can be compared with a twisted rope ‘ladder’. The nature and characteristics of DNA had been succinctly explained by Lord Justice Phillips in Regina v. Alan James Doheny & Gary Adams, 1997 (1) Criminal Appeal Reports 369.

In an early case of Frye v. United States, 54 App. D.C. 46 (1923) it was laid down, scientific evidence is admissible only if the principle on which it is based is substantially established to have general acceptance in the field to which it belonged. US Supreme Court reversed the above formulation in Daubert v. Merrell Dow Pharmaceuticals, Inc., 113 S.CT. 2786 (1993). The principle was summarized by Blackmun, J., as follows:

“To summarize: ‘general acceptance’ is not a necessary precondition to the admissibility of scientific evidence under the Federal Rules of Evidence, but the Rules of Evidence – especially Rule 702 – do assign to the Trial Judge the task of ensuring that an expert’s testimony both rests on a reliable foundation and is relevant to the task at hand. Pertinent evidence based on scientifically valid principles will satisfy those demands.”

After Daubert, the DNA test has been frequently applied in the United States of America. DNA technology as a part of forensic science and scientific discipline not only provides guidance to investigation but also supplies Court accrued information about the tending features of identification of criminals. The recent advancement in modern biological research has regularized forensic science resulting in radical help in the administration of justice. In our country also like several other developed and developing countries, DNA evidence is being increasingly relied upon by Courts. After the amendment in the Criminal Procedure Code by the insertion of Section 53A by Act 25 of 2005, DNA profiling has now become a part of the statutory scheme.

In Mohammed Ajmal Mohammad Amir Kasab alias Abu Mujahid v. State of Maharashtra, (2012) 9 SCC 1 the accused was awarded Death Sentence on charges of killing large number of innocent persons on 26th November, 2008 at Bombay. The accused with others had come from Pakistan using a boat ‘Kuber’ and several articles were recovered from ‘Kuber’. The stains of sweat, saliva and other bodily secretions on those articles were subjected to DNA test and the DNA test matched with several accused.


It is quite clear, DNA report deserves to be accepted unless it is absolutely dented and for non-acceptance of the same, it is to be established, there had been no quality control or quality assurance. If the sampling is proper and if there is no evidence as to tampering of samples, the DNA test report is to be accepted.”

Hon’ble Justice Dipak MisraMukesh v. State for NCT of Delhi, [Criminal Appeal Nos. 607-610 of 2017].