“You are my brother,” the Moroccan vendor proclaimed to my father. All his life, my father's olive complexion, unlike that of any close relative, had drawn stares and comments. His parents fled Germany for America in the 1930s, but his dark skin, coupled with a thick, black beard, told a different story. That day in the Jerusalem marketplace was no exception.

Until my father's bone marrow closely matched a boy of Portuguese descent, we'd only speculated that his skin tone signaled Arabic roots. Finding out that he had genetic ties to the Iberian peninsula revised the story: Not only had our ancestors escaped Hitler, but also the Inquisition.