Question

The diagram below shows DNA banding patterns obtained after DNA samples collected from a crime scene were subjected to gel electrophoresis. Samples from crime scene are denoted by C and three suspects are represented by S₁, S₂, S₃.

1. Which suspect’s DNA sample matches the sample collected from the crime scene?
2. Mention the principle on which DNA profiling is based.

Answer 1

1. Suspect 2 (S₂) is the match.
2. DNA polymorphism, specifically variations in the VNTRs (Variable Number of Tandem Repeats) in the non-coding (satellite) segments of DNA, is the foundation of DNA profiling. Individual differences in these repeats result in unique banding patterns.