Abstract Detail

Systematics Section / ASPT

Zhang, Li-Bing [1], Kocyan, Alexander [2], Renner, Susanne S. [2], Simmons, Mark P. [1].

Family relationships and mating system evolution in Cucurbitales based on ten loci from three genomes.

The Cucurbitales comprise seven families: Anisophylleaceae, Begoniaceae, Coriariaceae, Corynocarpaceae, Cucurbitaceae, Datiscaceae, and Tetramelaceae. Most are small and poorly known, with the exception of the species-rich families Cucurbitaceae (ca. 750 species) and Begoniaceae (ca. 1,400 species). Flowers of Cucurbitales are unisexual or rarely hermaphroditic, with unisexually-flowered populations either monoecious, dioecious, or androdioecious. At the Botany 2003 meeting, we first reported o­n our o­ngoing molecular study, which aims at resolving family relationship in Cucurbitales as well as testing the monophyly of the order. To date, we have combined the plastid genes atpB, matK, ndhF, and rbcL, the trnL intron, the rpl20-rps12 and trnL-trnF intergenic spacers, the nuclear genes 18S and 26S rDNA, and the mitochondrial nad1 b/c intron (together ca. 11.5 kb) for 26 representatives of the seven ingroup families and seven outgroup taxa from the six closest orders of Rosids I. The Cucurbitales are resolved as monophyletic and so are the six families for which two or more taxa were sampled. The Anisophylleaceae are sister to the six other families and Cucurbitaceae sister to the remaining five, which in turn form two clades: Corynocarpaceae plus Coriariaceae, and Begoniaceae, Datiscaceae, and Tetramelaceae. Parsimony character-state reconstruction suggests multiple independent shifts between dioecy and monoecy, as we are also finding within Cucurbitaceae (Kocyan, Zhang, and Renner, this meeting). Unexpectedly, perfect flowers in Coriariaceae and Corynocarpaceae are inferred to have evolved from unisexual flowers.

1 - Colorado State University, Department of Biology, Fort Collins, Colorado, 80523-1878, U.S.A.
2 - Ludwig-Maximilians Universitaet Muenchen, Faculty of Biology, Munich, D-80638

Keywords:
Begoniaceae
Cucurbitaceae
Cucurbitales
Datiscaceae
monoecy
dioecy
androdioecy
Coriariaceae
Corynocarpaceae
Anisophylleaceae
Tetramelaceae.

Presentation Type: Paper
Session: 38-4
Location: Cottonwood A (Snowbird Center)
Date: Tuesday, August 3rd, 2004
Time: 2:45 PM
Abstract ID:377