The 6 degrees theory has always fascinated me, but how about from a deeper, biological level rather than the social one that is normally talked of....

Does biology support the possibility that I am separated chemically, as opposed to socially, to my neighbour? Or the nest poster in this thread? Or even, perhaps, a sloth??

The idea that everyone is at most six steps away from any other person on Earth may be correct but from a biological and genetic perspective it is only one step. All Modern humans (Homo sapiens), evolved in Africa about 200,000 years ago and started to migrate from Africa to the rest of the world about 70,000 years ago. Therefore you can see that gentically we are all very similar and closely related. I suppose you could think of primates and monkeys as steps 2 and 3 in the "relatedness index".