Abstract Detail


Zhou, Wenbin [1], Xiang, Jenny [2].

Phylogenomics of Castenea, Hamamelis, and Torreya inferred from RAD-Seq data – Insights into origin and evolution of eastern Asia-North American disjunct biogeography pattern.

The eastern Asian (EA)-North American (NAM) floristic disjunction represents a major pattern of northern hemisphere biogeography and has been the subject of active studies during the past two decades. Application of a phylogenetic approach with molecular data and development of model-based statistic biogeographic methods have led to advancement in our understanding of the timing and migration routes of the origin. However, the mechanisms maintaining the floristic similarity in these long-term isolated geographic regions have remained unclear, which is partly due to that the evolution of plant taxa subsequent to the geographic isolation is not well-understood. Morphological evolution of closely related species in the two geographic areas has been considered slow due to climatic similarity in the two areas. With the advent of high-throughput DNA sequencing technology, robust phylogenies can be reconstructed from genome-wide markers for testing previous few gene data-based hypotheses regarding the origin and evolution of this biogeographic pattern, and for examining evolution of characters and molecules in the disjunct taxa. We reconstructed the phylogenies of three EA-ENA disjunct genera using RAD-seq data (Castenea, Hamamelis, Torreya). Through phylogenomic and biogeographic analyses and divergence time dating, we evaluated the previous hypotheses about their biogeographic histories. Using comparative analyses of evolutionary divergence in morphologies, DNA molecules, and climatic niches, we tested the hypotheses of “morphostasis” and climatic similarity. For each genus, analyses of phylogeny, divergence time, and biogeography were performed using maximum Likelihood and Bayesian Inference methods, BEAST, and DEC model, respectively. Phylogenetic analysis of morphological data matrix for each genus will be performed using parsimony and ML method constrained by the molecular phylogeny. Pairwise similarity in morphology was also calculated using Gower’s distance method. The relationship between the morphological and molecular divergence level/distance will be assessed to gain insights into the relative rates of morphological and molecular evolution. The evolution of climatic niches is investigated based on the phylogeny to determine if there is divergence between the species/clades in the two regions.

1 - North Carolina State University, Plant & Microbial Biology, Box 7612, 100 Derieux Place Gardner Hall 2115, Raleigh, NC, 27695, United States
2 - North Carolina State University, Plant And Microbial Biology, Campus Box 7612, Gardner Hall 2115, Raleigh, NC, 27695, United States

EA-NAM disjunction
biogeographic history
morphological evolution
niche evolution.

Presentation Type: Oral Paper
Abstract ID:889
Candidate for Awards:None

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