Lawyers now focus on DNA testing to prove the guilt or innocence of those accused of crimes, pushing traditional techniques such as fingerprint analysis into the background.
Identical twins develop when a single fertilized egg splits in two, leading to two embryos.
Because they both came from the combination of the same egg and sperm, they have identical DNA, barring the generally undetectable micromutations that begin as soon as cells start dividing. To a standard DNA analysis, they would be indistinguishable. Yet the parents of twins can usually tell them apart by subtle visual cues, and, while their fingerprints are generally similar, they are not identical. Fingerprints and physical appearance in general are part of an individual's phenotype, which arises from the interaction of the individual's genes and the developmental environment in the uterus. In the case of fingerprints, the genes determine the general characteristics of the patterns that are used for fingerprint classification.