In his letter dated may 5 1866, George Haines states that Indian traits are only showing up in the male descendants of Mary Carlile. And that the female descendants show no sign of Indian blood. But genetically this is precisely what one would expect to find if Mary were indeed an Indian. I am going to be a little technical here, but please bare with me. If Mary was an Indian maiden she would pass on the Indian gene in both her XX (chromosomes) In her sons (YX) there would be no X from the father to cancel out the Indian traits, so the SONS would show clear signs of Indian blood. The daughters however would carry two (XX) chromosomes from both father(X) and mother(X) with the fathers dominate gene cancelling out the Indian traits passed on from the mother. But half their daughters would pass on the Indian gene to their children. This same pattern would continue generation after generation up until the present day with the Indian gene showing up randomly, but only among the male members of the Family.  Precisely what George Haines observed. 

I can attest to the truth of this because my grandfather, Charles Bozarth Haines clearly had some Indian characteristics. Even to the point that my uncles would often refer to him as "Cherokee" I never understood why until now