Abstract Detail

Phylogenomics

Zuo, Lei [1], Freudenstein, John [2].

Phylogenomic analyses based on nuclear and plasmid data yield novel insights into the reticulate evolution of Asarum (Aristolochiaceae).

Hybridization has increasingly been regarded as one of the resources that drives evolution and also complicates the evolutionary relationship among species. As a result, efforts to reconstruct a strictly bifurcating tree for testing related evolutionary hypothesis have often suffered from reticulate evolution introduced by such processes. This appears to be true in Asarum (Aristolochiaceae), a group of herbs mainly distributed in east Asia and North America. Previous attempts have been made to uncover evolutionary relationship within this genus. However, either because of not enough data or being unaware of potential hybridization and a strictly bifurcating history being assumed, the tree topologies were usually either weakly supported or unstable and incongruent between different data matrixes and tree building methods. Some conclusions (intrageneric relationship, character evolution and biogeographic history) made based on those tree topologies are thus questionable. By using targeted nuclear (ca. 1.7 Mbp) and chloroplast (ca. 140 Kbp) DNA sequences, we performed a series of phylogenetic analyses and find strong discordance between and within nuclear and chloroplast data. Taking into account other factors (e.g., incomplete lineage sorting) that may have also contributed to discordant signals, we reconstruct phylogenetic networks and for the first time reveal complicated reticulate evolution within this genus. This further allows us to re-examine the hypotheses previously being tested based on poor data. Our primary result shows that: 1) a fully supported and updated intrageneric relationship is confirmed; 2) ancient hybridization within this genus may be more common than previously expected; 3) an alternative radiation history of subgenus Heterotropa mainly distributed in Japan-Ryuku-Taiwan island arc may be possible.

1 - The Ohio State University, 1315 Kinnear Rd, Columbus, OH, 43212, United States
2 - The Ohio State University, 1315 Kinear Rd, Columbus, OH, 43212, United States

Keywords:
Asarum
reticulate evolution.

Presentation Type: Oral Paper
Number: PHYLO I006
Abstract ID:811
Candidate for Awards:None