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Source- This post on DNA Profiling has been created based on the article “DNA profiling and its value in establishing guilt or innocence” published in “The Hindu” on 9 August 2024.
Why in News?
In mid-June, the Madras High Court overturned the conviction of a man in a POCSO rape case, citing insufficient proof by the prosecution. The court questioned the sole reliance on DNA evidence for establishing guilt, noting the victim’s false accusation as a key factor in the wrongful conviction. This has increased the focus on the process of DNA profiling.
What is DNA?
1. DNA stands for Deoxyribonucleic Acid, which is the genetic material present in the nucleus of almost all cells in living organisms.
2. It carries information that determines the internal organization, physical characteristics, and physiological functions of the body.
3. DNA is made up of four nucleotide bases: Adenine (A), Guanine (G), Thymine (T), and Cytosine (C), arranged in a double-helix structure.
About DNA Profiling
1. DNA profiling is a method used to identify individuals based on their unique DNA sequences.
2. Although 99.9% of human DNA is identical, the remaining 0.1% contains variations that can be used to create a DNA profile.
3. Specific locations in this 0.1% are examined, focusing on Short Tandem Repeats (STRs), which are repetitive sequences of DNA that vary from person to person.
About Process of DNA Profiling
| Process | Description |
| Sample Collection | 1. DNA can be collected from various biological materials like blood, saliva, semen, hair, or skin cells. 2. The process of collecting, storing, and transporting DNA samples is crucial to avoid contamination and ensure the accuracy of the results. |
| Laboratory Analysis | 1. DNA profiling involves several steps: isolating DNA from the sample, amplifying specific genetic markers, and analyzing these markers to create a DNA profile. 2. The key steps are isolation, purification, amplification, visualization, genotyping, and statistical analysis. |
How reliabile is DNA Profiling
1. DNA profiling is a powerful tool in forensic science, but it is not infallible. The process is based on probability, and various factors like sample contamination, degradation, or mishandling can affect the results.
2. The reliability of DNA evidence also depends on the quality of the sample and the expertise of the laboratory performing the analysis.
DNA Profiling in Criminal Cases
1. Role in Establishing Guilt or Innocence: DNA evidence can be critical in criminal investigations, helping to identify or exclude suspects. However, DNA evidence alone may not be conclusive.
2. Courts often require additional evidence to corroborate DNA findings before reaching a verdict.
3. In legal cases, the probative value of DNA evidence can vary. Courts may treat DNA evidence as strong, but not absolute, and it must be weighed alongside other evidence.
4. The absence of DNA evidence does not automatically imply innocence or guilt; other evidence may still be critical to the case.
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