Neil wrote, "I'm wondering how slaves and their children were 'incorporated
into society' in any meaningful number when slave-descendants are apparently
scant in the Middle-East."
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I mentioned the book "Islam's Black Slaves" by Segal and Douglas Deal 
suggested a more thorough analysis: John Hunwick and Eve Troutt Powell, /The 
African Diaspora in the Mediterranean Lands of Islam/ (Princeton, 2002).

I spent quite a bit of time in Saudi Arabia where the people range in color 
from nearly white to as dark as any African. It would not surprise me if 
half their DNA was African. The DNA came mostly from female slaves whose 
children were usually emancipated. They show little color consciousness, but 
a very light-skinned Saudi would almost never marry a very dark-skinned one.

Egypt was one of the major slave trading markets, and that may have affected 
their multi-colored complexions. I visited Oman which one might easily 
mistake for an African country because of their contact with Zanzibar and 
the East African coast. Many women wear African dress, and they allow anyone 
from East Africa who can prove Omani descent to return to Oman as a citizen. 
I met Tanzanian-Omanis there who still speak Swahili among themselves and 
are as dark as any Tanzanian.

Also, some people in parts of India could be mistaken for African for very 
good reason. They descend from male soldiers who became part of the free 
population. There is African DNA in every North African country, Spain, and 
every country from Turkey to Iran to China.
Paul