Do we have areas of our bodies with different genetics?
A more extreme form of different DNA is You are not allowed to view links.
Register or Login, where cells from a baby may live on in the mother's body (or vice-versa). Even more extreme is You are not allowed to view links.
Register or Login, where two fertilized egg cells may merge, producing an individual who has different organs with different DNA. This has produced some weird results when DNA tests are run, like "your child is actually your nephew".