Here is a cool thing;
Mesolithic Europeans were apparently three different quasi ethnicities and because populations aren't entirely homogenous, their DNA persist in various ways to this day. One really weird thing is that a significant chunk of European ancestors were way closer to Native Americans.
@Leucrotta Yup~ An original wave of people that mostly hung out in the western side of Europe, farmers that came in from the Middle East and a group that shares common ancestry with modern day Native Americans towards the east - the latter of which we (read: everyone who speaks English, or really any Indo-European language at all) also most likely ultimately got our language from.