But archeological investigations have some very real drawbacks.
Relics are few, widely scattered, and hard to locate.
Which ones are studied depends heavily on chance. And many important and potentially revealing materials, including flesh, wood, leather, and textiles, almost always decay before excavators unearth them. Instead of depending solely on chance finds of random remains, science has now uncovered a far more powerful and reliable record of the human past, as Luigi Luca Cavalli-Sforza shows in his concise and provocative introduction to a field that could accurately be called genetic archeology. In every cell of our body, each of us carries genes passed down to us from the countless generations of our ancestors. Coded within these genes is a history of where those ancestors were, what conditions they faced, and how they adapted to them.