Evolution on Islands: a colloquium to honor the careers of Daniel Crawford and Tod Stuessy
Lowrey, Timothy , Whitkus, Richard .
Evolution, Genetics, and Systematics of Tetramolopium and Vittadinia (Asteraceae: Astereae) in the Pacific Basin.
Tetramolopium is a wholly insular genus of small subshrubs that has an unusual pattern of distribution on the Hawaiian Islands, Cook Islands and New Guinea. Vittadinia is a largely Australian genus with species in Tasmania, New Zealand, and New Caledonia. We present a summary of our molecular, genetic, morphological, and hybridization studies on these two genera that elucidate their phylogenetic and biogeographic relationships, systematics, and evolutionary patterns. Molecular phylogenetic and morphological analysis reveals that Tetramolopium and Vittadinia should be combined into one genus. Also, the segregate genus Peripleura is nested within theTetramolopium-Vittadinia clade and sister to Hawaiian Tetramolopium. Hybridization studies reveal that crosses involving Hawaiian Tetramolopium and Australian Peripleura yield fertile hybrids. Hawaiian Tetramolopium exhibits changes in sex expression among species involving the presence of male sterility or fertility in disk florets. Genetic analyses show that two genes with modifiers mediate the genetic control of female disk fertility. The phylogenetic relationships suggest that the complex biogeographic pattern of the group has resulted from dispersal events from Australia to New Guinea, Hawaiian Islands, New Zealand, and New Caledonia. The Cook Island species has most likely been derived from a secondary dispersal event from the Hawaiian Islands.
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1 - University Of New Mexico, Department Of Biology, Albuquerque, NM, 87131, USA
2 - Sonoma State University, Department Of Biology, 1801 E Cotati Avenue, ROHNERT PARK, CA, 94928-3609, USA
Presentation Type: Symposium or Colloquium Presentation
Location: Franklin A/Hyatt
Date: Wednesday, July 11th, 2012
Time: 8:45 AM