How DNA Works
DNA (deoxyribonucleic acid) is present in the nucleus of a cell as a double helix, supercoiled to form chromosomes along with intercalated proteins.
Each person inherits 23 chromosomes from each parent.
DNA encodes physical and physiological traits using a sequence of four bases (Adenine, Guanine, Thymine, Cytosine).
Since the same DNA sequence is present in every cell of the body (apart from mature red blood cells) therefore, DNA can be sourced from any biological material
DNA is extracted from various biological materials (blood, saliva, hair).
Proper collection and handling are crucial to avoid contamination.
Involves isolating, purifying, amplifying, and analyzing specific genetic markers (Short Tandem Repeats or STRs) to create a DNA profile.
Reliability and Limitations
DNA profiling provides probabilistic rather than conclusive evidence.
Errors can occur due to sample contamination or mishandling.
Outcomes can be a match, exclusion, or inconclusive.
Matching DNA does not guarantee absolute identity due to possible random occurrence in the population.
Court Considerations
DNA evidence is useful for investigation but must be corroborated by other evidence in court.
The weight of DNA evidence varies by case and should not be the sole basis for conviction.
Courts recognize that while DNA analysis is highly reliable, it is not infallible
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