[BoomBully]

This is very common among Mexican families. I have a cousin who has really dark opaque skin, almost like a black person, but his sister got light skin, like an olive italian complexion. You can tell they're siblings because of their features but skin-wise they're so different.
This kind of thing happens a lot in Mexico and I bet many other latinamerican countries. I remember back in middle school I had a friend who was a blond with green eyes and light-tanned skin and her brother was a black haired guy with brown skin.