A novel at turns exuberant and wise, in the vein of The Family Fang and The Portable Veblen, about estranged half-siblings yoked together on a swampy Gulf Coast island after their biologist father's drowning. Welcome to Leap's Island, where a group of fringe scientists are obsessively studying the Undowny Bufflehead, a rare species of sea duck whose loss of waterproof feathers proves, they say, that evolution is running backward. Into this world of so-called "Reversalists" come Elsa and Nolan Grey, a half-brother and sister whose father, Dr. Ian Grey, has recently drowned while desperately trying to prove his own evolutionary theories. His estranged children find themselves on a pilgrimage to jointly reclaim his belongings and his memory, and to try to understand the stakes of the research he abandoned them to pursue. The Grey children, as the islanders come to call them, despite their being 35 and 29 years old, are incredulous that their brilliant father could have believed in Reversalism's pseudo-science. But as the siblings search for an elusive sea bird, confront the island's eccentrics, and hunt for signs their father still believed in progress, a darker question haunts them: is it their fault Dr. Ian Grey gave up on us all? Delightfully funny and fiercely original, Family of Origin grapples with questions of nature and nurture, evolution and mating, intimacy and betrayal, progress and forgiveness.