Rapid radiation of North American desert genera of the Papaveraceae: Evidence from restriction site mapping of PCR-amplified chloroplast DNA fragments

Abstract

Phylogenetic relationships of a group of North American desert genera of the Papaveraceae subfam. Papaveroideae and Platystemonoideae were investigated with an RFLP analysis of three PCR-amplified chloroplast genome regions. In agreement with earlier results it was found that subfam. Platystemonoideae is nested within subfam. Papaveroideae. The group under study is characterized by a large number of generic autapomorphies but only few informative synapomorphies. This is interpreted as strong evidence for a rapid radiation event caused by major climatic changes in the past. Poor phylogenetic resolution seems to reflect biological reality and not to be an experimental artifact. There is also evidence for accelerated morphological evolution under arid climatic conditions.