As far as I understand, although it is widely accepted that all hominids (neanderthals, homo erectus etc.) originated in Africa, there is no conclusive evidence to prove this theory a 100%.  However, as far as our particular species (Homo sapiens) is concerned, the fact that both the mitochondrial dna and y-chromosomal dna( in men) of all existing humans can be traced back to african origin seems like a conclusive evidence that supports the idea that we are africans afterall. Please let me know if I'm missing something here.