I was reading about a tribe in Africa and how they have not changed there ways for thousands of years. There are a few of these tribes left in the world. All these tribes can only have 3 outcomes. They breed with us, they go extinct, or they remain the way they are. If the third prevails then it is just a matter of time before we can no longer call ourlseves human. They will be the humans as they are the ones not changing. After some time we will not be able to breed with these people. (I hope no one takes any of this as racist). What I want to know is how much of our DNA has to be different before we can no longer breed. Have then been DNA testing on any of these tribes? Do we know how long this will take? do we already know what we are going to call ourselves?