did i say either of those things? slavery has been around in every civilization i can think of. when was it based on skin colour? in rome? no. in greece? no. to my knowledge it never was - correct me if i'm wrong. also, i know there are racist people everywhere. my perception, and i wouldn't be surprised to be shown wrong, is that it is a recent thing that people hate others based on morphology. in the past, i get the impression that people were wary of anybody outside their own particular group so hate wasn't based solely on race, or what others looked like.
the question was 'what are the roots of racism?'. i don't know. but to my knowledge, the first time that a group of people was discriminated against based on skin colour, which makes it an extremely broad group, was when someone noticed that in the states, slaves were black, slave-owners were white. the only other example i can think of is the hatred towards jews that everyone seems to have exhibited but that isn't racism since judaism is a religion.
finally, before like the 18th century or something 'racism' couldn't really have existed since no one had thought of the artificial divisions of race yet. so maybe the real answer lies with the people who thought this whole 'race' thing up and the answer to the roots of racism is europe