Phylogenetic Relationships of Saccharinae and Sorghinae
Multiple taxonomic and phylogenetic studies have been conducted on sugarcane, Miscanthus, and sorghum, but to date the results have been contradictory and somewhat confusing. A few generalities have emerged. The Andropogoneae is clearly monophyletic. Sacc
- PDF / 521,351 Bytes
- 19 Pages / 439.37 x 666.14 pts Page_size
- 90 Downloads / 236 Views
Phylogenetic Relationships of Saccharinae and Sorghinae Elizabeth A. Kellogg
Abstract Multiple taxonomic and phylogenetic studies have been conducted on sugarcane, Miscanthus, and sorghum, but to date the results have been contradictory and somewhat confusing. A few generalities have emerged. The Andropogoneae is clearly monophyletic. Saccharum and Miscanthus are closely related to each other. Their relationship with Sorghum is less clear, although they are probably more closely related to Sorghum than any of them is to maize or to Andropogon and its immediate relatives. The phylogeny of Andropogoneae is largely unresolved, which leads to a number of problems of taxonomic nomenclature. The solution will require considerably more phylogenetic data on a much broader set of species than has been sampled to date. Keywords Evolution • Phylogeny • Andropogoneae • Miscanthus • Polyploid • Classification • Sorghum • Sarga
1
Introduction
Sugarcane, Miscanthus, and sorghum are all members of the grass family, Poaceae. The first two are currently placed in the subtribe Saccharinae, whereas sorghum is often given its own subtribe, Sorghinae; both subtribes belong to the tribe Andropogoneae. Understanding the relationships of the three taxa is complicated by considerable phylogenetic uncertainty and taxonomic confusion. As described below, the phylogeny represents a difficult phylogenetic problem, in which rapid speciation early in the history of the group led to a phylogenetic tree with many very short internal branches. Disentangling this history has been complicated by a
E.A. Kellogg (*) Department of Biology, University of Missouri, One University Blvd, St. Louis, MO 63121, USA e-mail: [email protected] A.H. Paterson (ed.), Genomics of the Saccharinae, Plant Genetics and Genomics: Crops and Models 11, DOI 10.1007/978-1-4419-5947-8_1, © Springer Science+Business Media New York 2013
3
4
E.A. Kellogg
limited sample of species in all studies to date. In addition, the group includes many polyploids, sugarcane and Miscanthus among them, whose evolution is likely to be highly reticulate; while molecular phylogenetic approaches can disentangle net-like histories, this has not yet been attempted in the Andropogoneae. In this chapter, I take a hierarchical approach, beginning with the placement of Saccharinae and Sorghinae in the angiosperms, and noting the characteristics that have originated at various stages in evolution. I then consider the placement of the groups within the phylogeny of Andropogoneae, and discuss some of the implications and limitations of the phylogeny for understanding morphological and chromosomal evolution. In the final section, I consider the implications of the phylogenetic data for classification. Although I may not eliminate any taxonomic confusion, I hope to explain at least why it has occurred and what information might address the problems in the future. One likely conclusion from the available data is that the subtribe Saccharinae will ultimately be merged with the subtribe Sorghinae, and that t
Data Loading...
