She then explains that genetics suggests that all non-Africans may descend from a single, small group of Africans who left the continent tens of thousands of years ago. She explores various theories as to the route they took. She describes the Jebel Qafzeh remains in Israel as a likely dead end of a traverse across Suez, and sees a route across the Red Sea and the around the Arabian coast as the likelier route for modern human ancestors, especially given the lower sea levels in the past.