Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If You Use a Screen Reader

This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.

Congruence, Conflict, and Polyploidization Shown by Nuclear and Chloroplast Markers in the Monophyletic "Bristle Clade" (Paniceae, Panicoideae, Poaceae)

Andrew N. Doust, Anya M. Penly, Surrey W. L. Jacobs and Elizabeth A. Kellogg
Systematic Botany
Vol. 32, No. 3 (Jul. - Sep., 2007), pp. 531-544
Stable URL: http://www.jstor.org/stable/25064265
Page Count: 14
  • Read Online (Free)
  • Download ($12.00)
  • Subscribe ($19.50)
  • Cite this Item
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Congruence, Conflict, and Polyploidization Shown by Nuclear and Chloroplast Markers in the Monophyletic "Bristle Clade" (Paniceae, Panicoideae, Poaceae)
Preview not available

Abstract

Molecular phylogenetic analyses using the chloroplast marker ndhF and a single copy nuclear marker, knotted1, show that the panicoid grasses bearing sterile branches (bristles) in their inflorescences form a monophyletic group. The genus Cenchrus is monophyletic, and monophyly of Pennisetum cannot be ruled out. Setaria is not monophyletic, either as a whole, excluding the palm-leaved species from section Ptychophyllum, or excluding various uncertainly placed species such as S. grisebachii. There is also no evidence that Setaria and Paspalidium form a monophyletic group. The Australian genera Zygochloa, Spinifex, and Pseudoraphis are placed in the 'bristle clade', confirming that inflorescences of these grasses are homologous with the inflorescences composed of spikelets and sterile branchlets (bristles). Comparison of the nuclear and chloroplast gene trees identifies several taxa as tetra- or higher polyploids; these are confirmed by southern hybridization. In particular, the Australian species of Paspalidium are allopolyploid, a novel and unexpected result. Zuloagaea bulbosa, a species that lacks the synapomorphic bristles in its inflorescence, is confirmed as a morphologically anomalous member of the clade, and is clearly allopolyploid. This study demonstrates the utility of knotted1 as a phylogenetic marker; we show that it is single copy in diploid taxa and that it exhibits adequate variation to distinguish closely related species. Interestingly, inflorescence morphology correlates only partially with relationships suggested by either nuclear or chloroplast trees, suggesting that inflorescence form is easily changed over evolutionary time.

Page Thumbnails

  • Thumbnail: Page 
531
    531
  • Thumbnail: Page 
532
    532
  • Thumbnail: Page 
533
    533
  • Thumbnail: Page 
534
    534
  • Thumbnail: Page 
535
    535
  • Thumbnail: Page 
536
    536
  • Thumbnail: Page 
537
    537
  • Thumbnail: Page 
538
    538
  • Thumbnail: Page 
539
    539
  • Thumbnail: Page 
540
    540
  • Thumbnail: Page 
541
    541
  • Thumbnail: Page 
542
    542
  • Thumbnail: Page 
543
    543
  • Thumbnail: Page 
544
    544