DNA fingerprinting is possible because

  • A. every person has a completely different genetic code
  • B. only criminals have unusual DNA sequences
  • C. DNA differs between the cells of one person's body
  • D. the number of repeats in certain non coding sequences differs between individuals

Explanation

Short tandem repeats in non coding DNA vary greatly in number from person to person, so the pattern of band sizes is effectively unique except in identical twins. Half the bands of a child must match the mother and half the father, which is what makes paternity testing possible. The genetic code itself is the same in all people and indeed in all living things.

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