First, the ethnicity predictions are an infant science. Different companies will take the same data and give you different admixtures.

Second, you inherit half of your DNA from one parent and half from the other parent. On average you will share 50% DNA with a full sibling -- but that is an average. It is possible for 2 full siblings to share 0% DNA. What it means in the random dice game of DNA recombination while you got 50% of your mother's DNA your sibling managed to get the OTHER 50% you did not get, and the same with your father's DNA. Unlikely, but possible according to statistics.

Third, if you expand the sections on your ethnicity you will see that Ancestry gives you a range in addition to giving you a firm number. I'm guessing that if you look at the ranges instead of the hard numbers you will look more similar.

I really wish Ancestry wouldn't push the ethnicity in their ads -- it is such a 'soft science" right now.

Elizabeth