Ph.D. (Botany) University of Wisconsin
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The central goal of my research program is to understand the origin of plant diversity and mechanisms of speciation. I use molecular phylogeny and statistical inference to elucidate patterns and processes of evolution in angiosperms both at the interface of populations and species boundaries, and higher levels. Currently, I am using traditional phylogenetic methods to reconstruct dichotomously branching species relationships and newly developed genealogical methods to examine the potentially reticulate relationships of genes within and between populations of species. I have focused on island systems, and in particular the Hawaiian Islands, as a source of study organisms for modeling the evolutionary process for several reasons. First, the Hawaiian archipelago have been referred to as a “natural laboratory” for studying evolution in that these islands have never been connected to a continental mainland, and thus all life must have colonized from elsewhere. Also, their extreme distance from continental mainlands means that colonizing events are rare, and in the intervening time between colonization events, earlier colonizers have had the opportunity to undergo adaptive radiation and speciate into a multitude of highly related forms. Moreover, because the islands have formed consecutively as the Pacific plate moves over a stationary hotspot, the geological age of each island is known and each island represents a replicate system for examining patterns of coloniation and within-island speciation patterns. Thus, evolution on islands can be viewed as a surrogate for evolutionary processes occurring on mainlands, but in a more extreme and accelerated fashion. I have studied the evolution of two diverse plant groups on Hawaii, the large, pantropical shrub genus Psychotria (a member of the coffee family), which contains eleven species endemic to Hawaii, and the endemic Hawaiian genus Schiedea (a relative of carnations). I am interested in reconstructing evolutionary relationships within these lineages, their biogeographical relationships, and the evolution of plant structures in response to endogenous selection in insular habitats. I am also interested broadly in the development and application of bioinformatics tools to phylogenetic and genealogical problems. If you would like more information about my research projects click this link: Research Interests.
Bridget Jacobs: graduate student
T Tilottama Roy: graduate student
Dr. Ann Wilyard (post doctoral associate)
Former Undergraduate Researchers
Jeff Engemann ('07)
Holly Huse (Honors '06)
Bridget Jacobs (Honors '05)
Calvin Krogman (Honors '07)
Joanna Mehling (Honors 02)
Casey Griffith ('02)
Dr. Lisa Wallace, Assistant Professor of Biological Sciences, Mississippi State University
Eggens, F., M. Popp, M. Nepokroeff, W.L. Wagner, and B. Oxelman. 2007 The origin number of introductions of the Hawaiian endemic Silene species (Caryophyllaceae). American Journal of Botany 94: 210-218
Sakai, A., S.G. Weller, W.L. Wagner, M. Nepokroeff and T.M. Culley. Adaptive radiation and evolution of breeding systems in endemic Hawaiian Schiedea (Caryophyllaceae). (in press, 2006). Annals of the Missouri Botanical Garden. 93 (1).
Nepokroeff, M., W. L. Wagner, P. S. Soltis, S. G. Weller, D. E. Soltis, A. K. Sakai, & E. A. Zimmer. 2005. Phylogeny of Schiedea, in Wagner, Weller and Sakai, Monograph of Schiedea (Caryophyllaceae subfam. Alsinoideae). Systematic Botany Monographs 72: 13-20.
Sytsma, K.J., A. Litt, M.L. Zjhra, J.C. Pires, M. Nepokroeff, E. Conti, J. Walker, and P.G. Wilson. 2004. Clades, clocks, and continents: historical and biogeographical analysis of Myrtaceae, Vochysiaceae, and relatives in the southern hemisphere. International Journal of Plant Sciences 165 (4 Suppl.): S85-S105.
Nepokroeff, M., K. J. Sytsma, W.L Wagner and E. A. Zimmer. 2003. Reconstructing ancestral patterns of colonization and dispersal in the Hawaiian understory shrub genus Psychotria (Rubiaceae): A comparison of parsimony and likelihood approaches. Systematic Biology 52(6):820-838. (See review at Faculty of 1000).
Levin ,R., M. Nepokroeff, J. C. Pires, W. H. Wagner, P. C. Hoch, E. Zimmer & K. J. Sytsma. 2003. Family-level relationships of Onagraceae based on chloroplast rbcL and ndhF data.. American Journal of Botany 90: 107-115.
Sytsma, K.J., J. Morawetz, J. C. Pires, M. Nepokroeff, E. Conti, M. Zjhra, J. C. Hall, and M. W. Chase. 2002. Urticalean rosids: circumscription, rosid ancestry, and phylogenetics based on rbcL, trnL-F, and ndhF sequences. American Journal of 89: 1531-1546
Nepokroeff, M. and E.A. Zimmer. 2002. Angiosperms. In: Biology, Macmillan Reference, USA.
Nepokroeff, M. 2002. Eudicots. In: Biology, Macmillan Reference, USA.
Nepokroeff, M., B. Bremer and K. J. Sytsma. 1999. Re-organization of the genus Psychotria (Rubiaceae) and tribe Psychotrieae inferred from ITS and rbcL sequence data. Systematic Botany 24(1): 5-27.
Nepokroeff, M. and K. J. Sytsma. 1999. Speciation in cloud forest members of Psychotria section Notopleura (Rubiaceae). Monteverde: Ecology and conservation of a tropical cloud forest. Nalini Nadkarni and Nathaniel Wheelwright, eds. Oxford University Press.
National Science Foundation, Biological Research Collections, DBI-0545102, “Herbarium Improvement & Development of a Consolidated Vascular Plant Database for Western SD, and Eastern WY”. PI Mark Gabel, Black Hills State University. Subaward to M. Nepokroeff., University of South Dakota. $26,189. 4/1/06-3/31/07.
http://www.bhsu.edu/artssciences/asfaculty/mgabel/herbariumdatabase/databaseIntroduction.html
2005 National Science Foundation, Systematic Biology and Biotic Inventories/Population and Evolutionary Processes: “Phylogeography of Hawaiian Schiedea: A multigene, coalescent approach”, PI Molly Nepokroeff, co-PI Lisa Wallace. $356,100.
2002 National Science Foundation, Major Research Instrumentation: Acquistion of Genetic Analyzer by University of South Dakota Evolutionary Genetics Research Group. PI. Molly Nepokroeff. Co-PIs: Hugh Britten, Kaius Helenurm, and John Swallow. $135,000.
Some links of interest:
Encyclopedia of Life: http://www.eol.org/
Images of Schiedea at Gerry Carr's Hawaiian Native Plant Genera at University of Hawaii
Flora of the Hawaiian Islands website at Smithsonian Institution
Society of Systematic Biologists
Joe Felsenstein's Phylogeny Program's website at University of Washington
E-mail Dr. Nepokroeff
