Abstract Detail


Lindelof, Kira [1], Zhou, Wenbin [1], Xiang, Jenny [1].

Phylogenomics of the Blue- and White-Fruited Dogwoods of Cornus L. - Insights into the Evolution of Eastern Asian-Eastern North American Disjunct Clades.

The eastern Asian (EA)-eastern North American (ENA) floristic disjunction represents a major pattern of phytogeography of the Northern Hemisphere. Despite many recent studies of taxa displaying the disjunct pattern during the past 20 years, its origin and evolution remain an open question, especially regarding the post-isolation evolution. The blue- or white-fruited dogwoods (BW) is the most species rich among the four major clades of Cornus L., consisting of ~35 species divided into three subgenera. The BW group provides an excellent example for biogeographic study of the EA-ENA floristic disjunction due to its diversity distribution centered in eastern Asia and eastern North America.  Species relationships and delineation have also remained poorly understood in the group. In this study, we combined data from genome-wide markers from RAD-seq, morphology, fossils, as well as ecological niche to understand species relationships, biogeographic history, and ecological niche and morphological evolution. Our phylogenomic analyses with RAxML and MrBayes recovered a strongly supported and well-resolved phylogeny of the BW group with three intercontinental disjunct clades; two of these are newly identified in this study. We were able to date the BW stem and the divergence of each disjunct clade using divergence time analyses with BEAST and treePL. Biogeographic analysis with a DEC-based total evidence-dated phylogeny integrating fossils and time slices model for dispersal resolved ancestral ranges of the three disjunct clades, most likely a result of dispersal via the North Atlantic and Bering Land Bridges. Character mapping with a stochastic model in phytools and comparison of ecological niche, morphospace, and rate of evolution indicated that the disjunct sisters exhibit different divergence patterns in morphology, and ecological niche. Significantly different ecology among disjuncts suggests a role of niche divergence in morphological evolution post isolation. Finally, we suspect that the total diversification bias of the BW group towards EA is a consequence of early diversification. These findings, in conjunction with previous studies, again suggest the EA-ENA disjunct floras are an assembly of lineages descended from the boreotropical or its descendent mesophytic flora through taxon-specific evolutionary pathways.

1 - North Carolina State Univeristy , Plant and Microbial Biology, Raleigh, NC, 27695, USA

eastern Asian-eastern North American disjunction
ecological niche and morphospace.

Presentation Type: Oral Paper
Session: PHYL1, Phylogenomics I
Location: Virtual/Virtual
Date: Monday, July 27th, 2020
Time: 12:45 PM
Number: PHYL1002
Abstract ID:889
Candidate for Awards:None

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