The process of DNA fingerprinting was invented by Alec Jeffreys at the University of Leicester in 1985. He was knighted in 1994.
The use of DNA sequences to identify individual persons is called DNA fingerprinting or DNA profiling. Because some part genome are highly variable, each person DNA sequence is unique and, like a traditional fingerprinting, provides a distinctive characteristic that allows identification. Today most DNA FINGERPRINTIG utilizes microsetallites, or short tandem repeat (STRs)
PCR – used to amplify DNA found at crime scene into an amount that can be analyzed Microsatelliteare typically detected with PCR The length of the amplified segment depends on the number of repeats • DNA from a person with more repeats will produce a longer amplified segment than will DNA from a person with fewer repeats. • DNA produced is identical to the original sample
The Process In a NutshellAmplified DNA samples are injected into acapillary. Fluorescent tags on the DNAfragments are excited by a laser, thefluorescence is recorded by a camera, andthis signal is converted into a “peak” by thecomputer software.
Used by FBI They have taken 13 STR loci These system was used in to know people who died in the collapse of world trade center.
Stage 1: Cells are broken down to release DNA Step 2:The DNA is cut into fragments using restriction enzymesStage 3: Fragments are separated on the basis of size using a process called gel electrophoresisStage 4: The pattern of fragment distribution is then analysed.