Please source your claim. My understanding is that there was no large-scale genetic replacement, and the Coptic language (descendant of the ancient Egyptian lan

Please source your claim. My understanding is that there was no large-scale genetic replacement, and the Coptic language (descendant of the ancient Egyptian language) was widely spoken until the 18th century or so (it's a strictly liturgical language now). There has been plenty of ethnic and cultural mixing, of course, as in most places (Christianization, Arabization, etc.).