_:b663966048 . _:b663966048 . _:b663966048 . _:b663966048 . _:b663966048 . _:b663966048 . _:b663966048 . _:b663966048 . _:b663966048 "Orthology that involves two genes when duplications more recent than the species split have occurred in one species but not the other." .