It was in my evolutionary biology class in college that I ran into a concept that blew my mind, and in many ways still does.
It was the idea that race is primarily a cultural feature, not a biological or genetic one. There is more genetic diversity amongst the people of sub-Saharan Africa -- people who many of us would lump together as "Black" -- than there is in the rest of the world combined. A typical person of western European descent is, our professor told us, closer genetically to a person from Japan than a Tswana man is to the !Kung woman he lives right next door to in Botswana, even though both have dark skin and generally "African features."
The researchers analyzed 3,609 individual DNA samples representing 215 different ethnic groups, and used software to compare various stretches of the DNA and assemble them using the technique called parsimony -- basically, creating a family tree that requires the fewest random coincidences and ad hoc assumptions. The result was an enormous genealogy containing 27 million reconstructed common ancestors. They then linked location data to the DNA samples -- and the program identified not only when the common ancestors probably lived, but where they lived.
I find this absolutely amazing. Using modern genetic analysis techniques, we can assemble our own family tree, with roots extending backwards tens of thousands of years and encompassing lineages for which we have no archaeological or paleontological records. With the number of connections the research generated, I have no doubt we'll be studying it for years to come, and have only started to uncover the surprises it contains.
But all part of living up to the maxim inscribed in the Temple of Apollo at Delphi -- γνῶθι σεαυτόν.