Modern-day Europeans descend from a very small gene group. This caused all the mutations that characterize them today, such as blue and green eyes and different hair colors. It's also what has caused them to have higher instances of cancer and other genetically-linked ailments (same thing that happened to Native Americans). Conversely it's the same variations that have given them so many geniuses.
By the way, Jews were depicted in Egyptian paintings as having red hair. That leads me to believe that Jews descend from a group of people who started out in Africa (like all humans), then went to the Middle East, north through the Caucasus, and then south again.









