The U.S. Constitutionâs 10th Amendment is arguably the most important of all the amendments in the brilliant document that helped shape the United States.
Not even identical twins have the same DNA--although theirs would be far closer than anyone else's. DNA changes over time. Odds of two siblings having the same DNA who did not split from the same zygote are vanishingly small.
Every cell in an individual, including those in blood, semen, and hair roots, has the same DNA, the molecule of heredity. Since each person's DNA is unique (unless he is an identical twin), it can be used for identification with near-perfect accuracy.