REGIONAL DIFFERENCES IN RATES OF PLANT SPECIATION AND MOLECULAREVOLUTION: A COMPARISON BETWEEN EASTERN ASIA AND EASTERN NORTH AMERICA
Open Access
- 1 October 2004
- Vol. 58 (10) , 2175-2184
- https://doi.org/10.1111/j.0014-3820.2004.tb01596.x
Abstract
The eastern Asian (EAS)-eastern North American (ENA) floristic disjunction is one of the best-known biogeographic patterns in the Northern Hemisphere. Recent paleontological and molecular analyses have illuminated the origins of the biogeographic pattern, but subsequent diversification and evolution of the disjunct floras in each of the two continents after isolation remains poorly understood. Although similar in climate and floristic composition, EAS has twice as many species as ENA in genera occurring in both regions. Explaining such differences in species diversity between regions with similar environmental conditions (diversity anomalies) is an important goal of the study of the global patterns of biodiversity. We used a phylogenetic approach to compare rates of net speciation and molecular evolution between the two regions. We first identified EAS-ENA disjunct sister clades from ten genera (Asarum, Buckleya, Carpinus, Carya, Cornus, Hamamelis, Illicium, Panax, Stewartia, and Styrax) that represent diverse angiosperm lineages using phylogenetic analyses of ITS (internal transcribed spacer of nuclear ribosomal DNA) sequence data. Species richness and substitution rate of ITS between sister clades were compared. The results revealed a pattern of greater species diversity in the EAS counterparts. A positive relationship between species diversity and ITS substitution rate was also documented. These results suggest greater net speciation and accelerated molecular evolution in EAS. The data support the idea that a regional difference in net speciation rate related to topographic heterogeneity contributes to the diversity anomaly between EAS and ENA. The close relationship between rates of ITS evolution and species richness further suggests that species production may be directly linked to rate of nucleotide substitution.Keywords
This publication has 86 references indexed in Scilit:
- Geographical distribution and ecological conservatism of disjunct genera of vascular plants in eastern Asia and eastern North AmericaJournal of Ecology, 2004
- Deterministic Plio‐Pleistocene extinctions in the European cool‐temperate tree floraEcology Letters, 2003
- An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG IIBotanical Journal of the Linnean Society, 2003
- The origin and evolution of tertiary relict florasPublished by Elsevier ,2002
- The Use of Geological and Paleontological Evidence in Evaluating Plant Phylogeographic Hypotheses in the Northern Hemisphere TertiaryInternational Journal of Plant Sciences, 2001
- Dispersal‐Vicariance Analyses of Intercontinental Disjuncts: Historical Biogeographical Implications for Angiosperms in the Northern HemisphereInternational Journal of Plant Sciences, 2001
- Internal Transcribed Spacer Phylogeny of the Asian and Eastern North American Disjunct Aralia Sect. Dimorphanthus (Araliaceae) and Its Biogeographic ImplicationsInternational Journal of Plant Sciences, 2000
- Timing the Eastern Asian–Eastern North American Floristic Disjunction: Molecular Clock Corroborates Paleontological EstimatesMolecular Phylogenetics and Evolution, 2000
- Evolution of Eastern Asian and Eastern North American Disjunct Distributions in Flowering PlantsAnnual Review of Ecology and Systematics, 1999
- Revealing the factors that promote speciationPhilosophical Transactions Of The Royal Society B-Biological Sciences, 1998