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.
Many genes have more than two possible alleles (such as in human blood groups), but remember; the individual still only has two alleles (one from mom, one from dad). Analogy: no matter how many colors of shirts available to buy in a particular style, so still only can have two (two of the same, or two different ones).