Several surname projects have had E3a show up in their surname projects
when there is no hint of a connection to sub-Saharan Africans (e.g., see
the Ivey surname project). E3a occurs at a very low level in Europe.
There may have been a connection in Roman times to Africans, but
nothing in the last few hundred years. My guess is that there is no
African-American connection, though it remains a theoretical
possibility.
Whit