The DNA fingerprint from a suspect can be compared to DNA found at the crime scene. If they don't match, then the suspect is cleared. In the last few years, DNA fingerprints have played a major role in clearing innocent suspects and freeing wrongly convicted prisoners. If the suspect's and crime scene's DNA do match, this does not necessarily mean the DNA at the crime scene belongs to the suspect. Since the print charts only a few sections of DNA, conceivably other people could share the same DNA print.
Scientists calculate the probabilities.
They do this by consulting databases of DNA patterns. They look to see how often each particular pattern, or band, in the bar code occurs in the general population or in the ethnic group of the suspect. By multiplying the odds of having each band, scientists calculate the odds of having all of them. Some critics believe DNA experts often overestimate the odds of having matching DNA fingerprints. They point out that people of the same ethnic group share more DNA and would be more likely to match DNA than people outside these groups.