Race, it works the other way as well...

My husband was born of two 'very white' parents, and all of his brothers are also white (he has 4 brothers), but he was born with very olive skin (that tans very easily and to a very dark color, with little effort); he has no freckles; black hair and virtually no body hair, it is plain as day that somewhere in his linage there is dark skinned genes, and he just happened to be in line to receive them.

He definitely stands out in the family as having a different genetic composition than the rest of his family...in many ways, not just skin color and appearance. He's the 'odd one out' so-to-speak...in a good way though.