Systematics Section / ASPT
Shak, Joshua R. , Levin, Rachel , Miller, Jill S. .
Phylogenetic relationships of Old World Lycium (Solanaceae): Reticulate evolution in the African taxa.
THE cosmopolitan genus Lycium (Solanaceae) contains ca. 80 species, of which 34 are native to Africa and Eurasia. We use DNA sequence data from both a nuclear (granule-bound starch synthase, GBSSI, waxy) gene and two chloroplast (trnT-trnL and trnD-trnT) regions to infer evolutionary relationships among the Old World species. This study included three of the seven Asian Lycium, all twenty-six named African species, and three newly collected, undescribed taxa from Africa. This is the first study to include complete sampling from Africa, one of the world’s hotspots of Lycium diversity (second only to South America). Consistent with previous studies, Old World Lycium are strongly supported as monophyletic. In addition, the chloroplast data show that the Asian taxa are monophyletic and nested within the African species, suggesting a single dispersal from Africa to Asia. Further, among the African species there are eight gender dimorphic taxa, and their phylogenetic distribution indicates multiple origins of separate sexes. Hybridization has been previously suggested as important in speciation among African Lycium. Using gene tree incongruence between the chloroplast and nuclear topologies and the paraphyly of GBSSI alleles in the polyploid species, putative hybrids and their parental lineages are suggested. Finally, we speculate on the prevalence of dimorphism among African Lycium as compared to American Lycium species.
Log in to add this item to your schedule
Miller Lab Website
1 - Amherst College, Department of Biology, Mcguire Life Sciences Building, Amherst, Massachusetts, 01002, USA
Presentation Type: Poster:Posters for Sections
Location: Auditorium/Bell Memorial Union
Date: Tuesday, August 1st, 2006
Time: 12:30 PM