Ann K. SakaiProfessor, Ecology & Evolutionary Biology |
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Research Interests |
plant population biology, plant breeding systems, population biology of invasive species | |
| URL | Lab web page | |
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Academic Distinctions |
Society for the Study of Evolution, Council member 2004-2006 Chancellor’s Award for fostering undergraduate research 2002 Senior Mellon Fellow, Smithsonian Institution 1994 |
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Research Abstract |
My research interests are in the areas of plant population biology and conservation biology. Much of my research focuses on the evolution of plant breeding systems. Most flowering plant species are hermaphroditic, but evolution of dioecy (separate male and female plants) has occurred independently in many lineages. I am interested in identifying the genetic and ecological factors that may promote the evolution of dioecy. These factors may include high inbreeding depression, high selfing rates, and changes in pollinators, habitat, and other ecological conditions. I have examined these questions in the Hawaiian flora, a flora which is particularly well suited for these questions because of its high incidence of dioecy. World-wide, the incidence of dioecy in only about 4% but in the Hawaiian Islands approximately 15% of species are dioecious. In collaboration with Stephen Weller, we have examined factors promoting the evolution of dioecy in Schiedea (Caryophyllaceae), a genus endemic to the Hawaiian Islands. Our work involves field studies of the pollination biology and ecology of populations in Hawaii, greenhouse studies of inbreeding depression, measurement of outcrossing rates by electrophoresis and molecular techniques, and phylogenetic analyses. Our current research is a quantitative genetics study of the genetic potential for changes in allocation patterns to male and female function in two gynodioecious Schiedea species, with measurements of narrow sense heritabilities, genetic correlations, and an artificial selection experiment. I am also interested in the evolution of heterostyly in the genus Oxalis. With a number of colleagues from the US and Mexico, we are investigating the evolution of distyly from tristyly in Oxalis alpina. I am also interested in issues related to conservation biology, particularly in the Hawaiian Islands. The native flora is disappearing at an alarming rate because of habitat destruction, feral goats and pigs, cattle grazing, and alien invasive species. I am interested in both the invasiveness of particular species and the invasibility of native communities, and how integration of the disciplines of population biology and invasion biology can lead to better understanding and management of alien invasive species. |
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| Publications | Wallace, L. E., S. G. Weller, W. L. Wagner, A. K. Sakai, and M. Nepokroeff. 2009. Phylogeographic patterns and demographic history of Schiedea globosa (Caryophyllaceae) on the Hawaiian Islands. American Journal of Botany 96: 958-967. | |
| Sakai, A. K., S. G. Weller , T. M. Culley, D. R. Campbell, A. K. Dunbar-Wallis, and A. Andres*. 2008. Sexual dimorphism and the genetic potential for evolution of sex allocation in the gynodioecious plant, Schiedea salicaria. Journal of Evolutionary Biology 21:18-29. | ||
| Poulin, J., A. K. Sakai, S. G. Weller, and T. Nguyen. 2007. Phenotypic plasticity, precipitation, and invasiveness in the fire-promoting grass, Pennisetum setaceum (Poaceae). American Journal of Botany. 94:533-541. | ||
| Weller, S. G., A. K. Sakai, T. M. Culley, D. R. Campbell, P. Ngo*, and A. K. Dunbar-Wallis. 2007. Sexually dimorphic inflorescence traits in a wind-pollinated species: heritabilities and genetic correlations in Schiedea adamantis (Caryophyllaceae). American Journal of Botany 94:1716-1725. | ||
| Weller, S. G., A. K. Sakai, D. R. Campbell, T. M. Culley, and A. Dunbar-Wallis. 2006. Predicting the pathway to wind pollination: heritabilities and genetic correlations of inflorescence traits associated with wind pollination in Schiedea salicaria (Caryophyllaceae). Journal of Evolutionary Biology 19: 331-342. | ||
| Sakai, A. K., S. G. Weller, W. L. Wagner, M. Nepokroeff, and T. M. Culley. 2006. Adaptive radiation and evolution of breeding systems in Schiedea (Caryophyllaceae), an endemic Hawaiian genus. Annals of the Missouri Botanical Garden. 93: 49-63. | ||
| Culley, T. M., A. K. Dunbar-Wallis, A. K. Sakai, S. G. Weller, and D. R. Campbell. 2006. Genetic variation of ecophysiological traits in two gynodioecious species of Schiedea (Caryophyllaceae). New Phytologist. 169: 589-601. | ||
| Golonka, A. M. , A. K. Sakai, and S. G. Weller. 2005. Wind pollination, sexual dimorphism, and changes in floral traits of Schiedea (Caryophyllaceae). American Journal of Botany 92:1492-1502. | ||
| Weller, S. G., A. K. Sakai, D. A. Thai, J. Tom, and A. E. Rankin. 2005. Inbreeding depression and heterosis in populations of Schiedea viscosa, a highly selfing species. Journal of Evolutionary Biology 18:1434-1444. | ||
| Culley, T. M., A. K. Dunbar-Wallis, A. K. Sakai, S. G. Weller, and D. R. Campbell. 2005. Genetic variation in ecophysiological traits and the evolution of gynodioecy in Schiedea (Caryophyllaceae). New Phytologist 169: 589-601. | ||
| Poulin J., S. G. Weller, A. K. Sakai. 2005. Genetic diversity does not affect the invasiveness of fountain grass (Pennisetum setaceum) in Arizona, California and Hawaii. Diversity and Distributions 11: 241-247. | ||
| Weller, S. G., and A. K. Sakai. 2005. Selfing and resource allocation in Schiedea salicaria (Caryophyllaceae), a gynodioecious species. Journal of Evolutionary Biology 18:301-308. | ||
| Wagner, W. L., S. G. Weller, and A. K. Sakai. 2005. Monograph of Schiedea (Caryophyllaceae subfam. Alsinoideae). Systematic Botany Monographs 72: 1-169. | ||
| Weller, S. G., A. K. Sakai, D. R. Campbell, T. M. Culley, and A. Dunbar-Wallis. 2005. Predicting the pathway to wind pollination: heritabilities and genetic correlations of inflorescence traits associated with wind pollination in Schiedea salicaria (Caryophyllaceae). Journal of Evolutionary Biology. 19: 331-342. | ||
| Rankin, A. E., S. G. Weller, and A. K. Sakai. 2002. Mating system instability in Schiedea menziesii (Caryophyllaceae). Evolution 56: 1574-1585. | ||
| Sakai, A. K., W. L. Wagner, and L. Mehrhoff. 2002. Patterns of endangerment in the Hawaiian flora. Systematic Biology 51: 276-302. | ||
| Sakai, A. K., F. W. Allendorf, J. S. Holt, D. M. Lodge, J. Molofsky, K. A. With, S. Baughman, R. J. Cabin, J. E. Cohen, N. C. Ellstrand, D. E. McCauley, P. O'Neil, I. M. Parker, J. N. Thompson, and S. G. Weller. 2001. The Population Biology of Invasive Species. Annual Review of Ecology and Systematics 32: 305-332. | ||
| Weller, S. G., A. K. Sakai, A. E. Rankin, A. Golonka, B. Kutcher, and K. E. Ashby. 1998. Dioecy and the evolution of wind pollination in Schiedea and Alsinidendron (Caryophyllaceae: Alsinoideae) in the Hawaiian Islands. American Journal of Botany 85:1377-1388. | ||
| Sakai, A. K., S. G. Weller, M.-L. Chen, S.-Y. Chou, and C. Tasanont. 1997. Evolution of gynodioecy and maintenance of females: the role of inbreeding depression, outcrossing rates, and resource allocation in Schiedea adamantis (Caryophyllaceae). Evolution 51:724-736. | ||
| Link to this profile | http://www.faculty.uci.edu/profile.cfm?faculty_id=2693 | |
| Last updated | 09/14/2009 | |