Once when I visited a museum on a field trip, the curator explained that it was because the gene for 6 fingers was actually very common among Ancient egyptians,

Once when I visited a museum on a field trip, the curator explained that it was because the gene for 6 fingers was actually very common among Ancient egyptians, and so the use of base-6 and base-12 number systems became popular in astronomy and architecture. I haven't heard that since, however, and I'm not sure how true it is.