Traces of Sub-Saharan African and Amerindian admixture in old stock European Americans:
Some people like to overestimate extra-European admixture in old stock Americans, while others take the position that it never happened. It did happen, and I can prove it, but certainly not to a great extent, otherwise I wouldn't be bending over backwards to find it. Basically, after some initial experiments, I can report that Sub-Saharan African segments of around 2 megabases or more show up regularly in my Southern European, old stock American and British samples. They're much less common in other individuals of European origin.
Why?
I believe that most of the Sub-Saharan African specific segments arrived in Southern Europe during the early middle ages, with Muslim invasions from North Africa. On the other hand, in the UK they're probably a legacy of the Roman Empire (see here) and slave trade, in which the British obviously played ...
