In gel electrophoresis, smaller DNA fragments outpace larger ones through microscopic pores, creating a molecular separation that reveals your unique genetic fingerprint. Each fragment's distance becomes a measurable identity marker. Drag the slider to control the electrical current and watch fragments separate by size.
Gel Chamber
100V — SLOW MIGRATION
Fragments separate based on size and applied voltage
SAMPLE LOADED — 100V APPLIED
Applied Voltage
50V150V250V
Migration Rate
1.0×
Separation
Low
DNA profiling in forensic science exploits short tandem repeats (STRs) — highly variable non-coding regions where individuals possess different numbers of repeated sequences at specific loci. Crime scene samples are amplified using PCR targeting multiple STR loci simultaneously, then separated by electrophoresis to generate a unique banding pattern. Each band represents one allele inherited from a parent at that locus. When comparing a suspect's profile to crime scene DNA, forensic analysts look for matching alleles at 13-20 different loci. The probability of two unrelated individuals sharing identical alleles at all tested loci is astronomically low — often less than one in several billion — making DNA profiling one of the most reliable forensic identification methods available.
Know This
Smaller DNA fragments move faster and travel further through gel pores than larger fragments, creating size-based separation that reveals unique genetic patterns inherited from both parents at each locus.