What is a DNA Fingerprint?
If we analyze the polymorphisms (small differences in the DNA sequence) within a person's genome, we can generate a unique "DNA fingerprint." After DNA is extracted from biological samples, scientists use the polymerase chain reaction (PCR) to amplify specific places (loci) throughout the genome. The PCR products are analyzed using agarose gel electrophoresis. The PCR products appear on the gel as a series of bands with various sizes. Because DNA samples from different individuals produce different patterns of bands, scientists can use a DNA fingerprint to distinguish between individuals.
The best-known application of DNA fingerprinting is in forensic science. DNA fingerprinting techniques are utilized to analyze blood, tissue, or fluid evidence collected at accidents and crime scenes. The DNA fingerprint from a crime scene can be compared with the DNA fingerprints of different suspects or those stored in CODIS (COmbined DNA Index System), a computer database of DNA fingerprints collected from convicted offenders, arrested persons, and crime scene evidence and missing persons. A match between the crime scene DNA and a suspect's DNA at a single locus does not prove guilt, nor does it rule out innocence. Therefore, multiple loci are tested. For example, the DNA fingerprints stored in CODIS contain data on thirteen loci. The odds of a match at all thirteen loci are less than one in a trillion!
Using our kits, your students will compare "crime scene" DNA with "suspect" DNA! Try our DNA Fingerprinting by PCR Amplification (Kit #130), DNA Fingerprinting Using Restriction Enzymes (Kit #225), or DNA Fingerprinting Using PCR (Kit #371)
Bring the exciting world of modern forensics into your classroom!