One would think that if we had all those different samples submitted down through the years, that we would surely be seeing groups forming from similar results/characteristics, and maybe some would indeed prove to be actually contaminated by the humans that collected them, but I'd bet baboons to bushbabies, that a good number of those discarded were in fact genuine unknown hominids, and of those there are bound to be clusters indicating either distinct species or populations that breed only amongst themselves, as well as forming a gradient in regards to how closely related to us they are.