It can mean a lot of things, but that seems like one of the less likely explanations.
It could just mean that the Egyptian royal family had a strong European strain at the time, from even a rather distant ancestor.
Cavalli-Sforza has shown that for the most part genetic variation among human populations is gradual by distance, barring isolation, except where a small pre-agricultural population was replaced by a much more numerous agricultural one - because agriculture supports orders of magnitudes more people.
Once there are millions of peasants living on the land it is quite difficult to get rid of them.
Egypt has been a crossroads for humanity for millenia. The people who live there now are not the descendants of the people who built the great civilizations of the past. The ancient Egyptians of the pre-Alexander era, were most likely traders with the Phoenicians (Carthage, Spain, Tyre and Sidon) and may have hitched a ride with them to southwestern Europe when things got heated in the wars with Babylon, Assyria and eventually Greece and Rome. When they moved out, the Arabs moved in....................