Abstract Detail

Phylogenomics

Hodel, Richard [1], Zimmer, Elizabeth [2], Liu, Bin-Bin [3], Johnson, Gabriel [4], Potter, Daniel [5], Wen, Jun [6].

Dissecting the role of reticulate evolution in the diversification of Prunus (Rosaceae).

The genus Prunus (Rosaceae) contains approximately 250-400 evergreen and deciduous species occurring in temperate and tropical regions. Recent phylogenetic analyses have identified three major groups within the genus, characterized by different inflorescence types. The well-studied, primarily diploid and temperate, solitary-flower and corymbose groups contain economically important species such as peaches, almonds, plums, and cherries. The polyploid racemose group is represented by hundreds of species in temperate regions of the Northern Hemisphere, the Neotropics, and the Paleotropics, but has been understudied relative to the corymbose and solitary groups. Previous phylogenetic studies have documented cytonuclear discord: phylogenies based on plastid DNA data resolve the racemose group as a clade sister to a solitary/corymbose clade, while nuclear data have not clearly resolved the relationships between the solitary/corymbose clade and the racemose lineages. These results have led to hypotheses of ancient hybridization and allopolyploidy to explain the origin of the racemose group of Prunus.
Here, we use 610 nuclear loci and plastid genomes generated via Hyb-Seq to resolve the phylogeny of Prunus using over 80 species representing all major clades and geographic regions of the genus. Species tree analyses revealed that the racemose group was paraphyletic in nuclear phylogenies, with the tropical and temperate racemose species forming two separate clades, the latter sister to the corymbose and solitary clades. In contrast, the racemose group was monophyletic in the plastid phylogeny, consistent with previous phylogenetic investigations based on plastid data. Analyses of discordance between gene trees and species trees, and comparisons of phylogenetic networks, provided several lines of evidence that hybridization and/or allopolyploidy contributed to a history of reticulation in Prunus, explaining the observed cytonuclear discord. We discuss the implications of our phylogenetic results on the biogeographic diversification and character evolution of this group.

1 - National Museum of Natural History, Botany, MRC 166, Smithsonian Institution, Washington, DC, USA
2 - Smithsonian NMNH, Botany MRC 166, P.O. Box 37102, Smithsonian National Museum Of Natural History, Washington, DC, 20013, United States
3 - Chinese Academy of Sciences, State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Beijing 100093, China
4 - National Museum of Natural History, Department of Botany, Smithsonian Institution, MRC 166, Washington, DC, 20560-0166, United States
5 - DEPARTMENT OF PLANT SCIENCES MAIL STOP 2, One Shields Avenue, Davis, CA, 95616, United States
6 - Botany, MRC-166 National Museum Of Natural History, 10th St. & Constitution Ave., NW, Mrc 166, Washington/DC, 20013, United States

Keywords:
allopolyploidy
hybridization
phylogenetic network
cytonuclear discord
Hyb-Seq
biogeography.

Presentation Type: Oral Paper
Number: PHYLO II007
Abstract ID:706
Candidate for Awards:None