Chimeric nature of atp1 in Pilostyles thurberi. A. Spatial delimitation of regions I and II of atp1 based on gene conversion analyses of sequence variation in Pilostyles and various Fabalean taxa. A region of 804 bp in Pilostyles (AZ) (region II) was inferred to be the result of gene conversion by an atp1 sequence from its host, Psorothamnus (P < 0.05). B. Single most likely tree obtained in phylogenetic analyses of regions I (-lnL = 883.42). C. Single most likely tree obtained in phylogenetic analyses of regions II (-lnL = 1383.82). Filled bar indicates caesalpinioid legumes and unfilled bar indicates faboid legumes. BP/PP values are shown above all nodes with values >50/0.8.