_:b662818219 . _:b662818219 . _:b662818219 . _:b662818219 . _:b662818219 . _:b662818219 . _:b662818219 . _:b662818219 . _:b662818219 "Orthology that involves two genes when duplications more recent than the species split have occurred in one species but not the other." .