How do people that are all the same nationalities look different?

Question

I'm mescalero apache (indian), Spanish, Polish, and Italian. My brother and sister are the same. My brother looks a lot like me but my sister is blonde. I know about the whole gene thing but can someone please explain to me in a way that I might be able to understand better?

Answer 1

http://learn.genetics.utah.edu/units/basics/tour/inheritance.swf

This was the simplest easiest to understand explaination I could find. It is a very interesting question with a even more interesting answer.
It is a "gene thing". Genetics is way beyond me in anything but the most basic (for genetics) way.
I hope the link helps.