Abstract Detail


Xiang, Jenny [1], Fu, Chaonan [2], Gao, Lianming [2].

Plastid Genome-based Phylogeny of Cornales – Insights Into Biogeographic History and Diversification.

The Cornales is a relatively small but morphologically diverse order sister to the rest of Asterids. Previous study hypothesized an ancient rapid radiation during the Cretaceous. The present study conducted phylogenomic analysis of Cornales using 81 plastid genome sequences to test the hypothesis. This sampling represented all of the families and 32 out of 42 genera in the order. We applied different character coding strategy for phylogenetic analyses and performed analyses of divergence time, diversification rate, and biogeographic analyses to understand the early evolutionary history of Cornales in space and time. A strongly supported congruent phylogeny was resolved by the datasets of amino acid sequences, nucleotide 1st and 2nd codon positions, all nucleotides with degenerated coding method, and nucleotides of noncoding regions. However, a placement of Hydrostachyaceae conflicting with this phylogeny was moderately supported by datasets of nucleotide characters of all codon positions and nucleotide 3rd codon positions, suggesting possible saturation of 3rd codon position. Results of divergence time analyses using BEAST and TreePL supported a rapid divergence of the order into major clades and families in the middle Cretaceous. The ancestral distribution of the order was inferred as the northern hemisphere but the specific range of the northern hemisphere depended on models and how the fossil data were used in the analysis. Origins of Hydrostachyaceae, Grubbiaceae, and Curtisaceae was inferred to have involved two independent dispersal events to Africa from the north. Diversification rate analysis detected shifts in two or four lineages of the phylogeny depending on the dated trees used. Our study demonstrated the importance and challenges of fossil data in biogeographic history inference, the impact of dated trees from different methods on detecting shifts in diversification rates, and caution with the 3rd position data from the plastid genome sequences in phylogenomic study.

1 - North Carolina State University, Plant And Microbial Biology, Campus Box 7612, Gardner Hall 2115, Raleigh, NC, 27695, United States
2 - Kunming Institute of Botany, Chinese Academy of Sciences, Laboratory for Plant Diversity and Biogeography of East Asia, Kunming, Yunnan Province, China

The complete cp genome phylogeny 

Presentation Type: Oral Paper
Abstract ID:523
Candidate for Awards:None

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