Chloroplast rbcL sequences of 60 species of Polystichum sensu lato (S.l.), including 23 new sequences from southwest China, were used to assess the phylogenetic relatipmships within the genus. On the basis of estimate...Chloroplast rbcL sequences of 60 species of Polystichum sensu lato (S.l.), including 23 new sequences from southwest China, were used to assess the phylogenetic relatipmships within the genus. On the basis of estimated evolution rate of rbcL gene and the genetic distance data that passed relative-rate tests, we further estimated the diver- gence times betwcen some clades of the genus. The phyloge- netic relationships were inferred using the neighbor-joining and maximim-parsimony methods, both methods producing trees with completely congruent topology. These trees reveal that all species of Polystichum s.I. in this study (including Cyrtomium and Cyrtomidictyum) form a monophyletic group. The basal split in Polystichum s.I. separates a clade with all Asian members from a elade containing other species from all over the world. The phylogenetic and divergence time estimation results lead us to suggest that Polystichum S.I. originated in Asia in the late Late Cretacous (≈76 Ma) and migrated into other places in the world in early Eocene (≈ 46 Ma).展开更多
文摘Chloroplast rbcL sequences of 60 species of Polystichum sensu lato (S.l.), including 23 new sequences from southwest China, were used to assess the phylogenetic relatipmships within the genus. On the basis of estimated evolution rate of rbcL gene and the genetic distance data that passed relative-rate tests, we further estimated the diver- gence times betwcen some clades of the genus. The phyloge- netic relationships were inferred using the neighbor-joining and maximim-parsimony methods, both methods producing trees with completely congruent topology. These trees reveal that all species of Polystichum s.I. in this study (including Cyrtomium and Cyrtomidictyum) form a monophyletic group. The basal split in Polystichum s.I. separates a clade with all Asian members from a elade containing other species from all over the world. The phylogenetic and divergence time estimation results lead us to suggest that Polystichum S.I. originated in Asia in the late Late Cretacous (≈76 Ma) and migrated into other places in the world in early Eocene (≈ 46 Ma).
