| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 5920603 | Molecular Phylogenetics and Evolution | 2011 | 11 Pages |
Molecular phylogeography can lead to a better understanding of the interaction between past climate events, large-scale vegetation shifts, and the evolutionary history of Neotropical seasonal forests. The endangered timber tree species Cedrela fissilis is associated with seasonal forests and occurs throughout South America. We sampled C. fissilis from 56 sites across the species' range in Brazil and Bolivia and obtained sequence data for nuclear and chloroplast DNA. Most specimens (149 out of 169) exhibited intraindividual polymorphism for the nuclear internal transcribed spacer (ITS). Cloning and an array of complementary sequence analyses indicated that the multiple copies of ITS were functional paralogs - concerted evolution in C. fissilis appeared to be incomplete. Independent Bayesian analyses using either ITS or cpDNA data revealed two separate phylogenetic lineages within C. fissilis that corresponded to populations located in separate geographic regions. The divergence occurred in the Early Pliocene and Late Miocene. We argue that climate-mediated events triggered dispersal events and split ancestral populations into at least two large refugial areas of seasonal forest that were located to the east and west of the present day Cerrado. Upon recent climate amelioration, formerly isolated lineages reconnected and intraspecific hybridization gave rise to intraindividual polymorphism and incomplete concerted evolution in C. fissilis.
Graphical abstractDownload full-size imageHighlights⺠Cedrela fissilis displayed intragenomic polymorphism for ITS. ⺠Both cpDNA and nuclear ITS suggests two separate phylogenetic lineages within Cedrela fissilis. ⺠The split into West and East lineage took place in the Early Pliocene and Late Miocene. ⺠Each lineage of Cedrela fissilis occur within seasonal forests located to the east and west of the present day Cerrado.
