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Dr. Andrew Schnabel

  • Dr. Andrew Schnabel
  • Department Chair and Professor of Biological Sciences
  • B.A. Oberlin College (1980)
  • Ph.D. University of Kansas (1988)
  • Office: Northside 134E
  • Phone: 574-520-4413
  • Email: ASchnabe AT


I regularly teach our first-semester course for biology majors, which covers fundamental principles of ecology, genetics and evolution, and our upper-level course in evolution, which provides a rigorous introduction to this core field of biology.  The theme of evolution has also figured prominently in courses I have taught for the Masters of Liberal Studies program, Evolution in the 21st Century and Evolution, Genetics, and Race.  In addition, I teach a variety of courses devoted to plant biology.  The primary example is Vascular Plants, which focuses on diversity, identification, and systematics.  I also teach botany courses for non-majors, and these typically cover a basic introduction to plant structure, function, ecology, and evolution, with added emphasis on the ways in which human societies make use of and are dependent upon plants.  Finally, I have mentored many students interested in conducting biological research.  These students have been active participants in several research projects, generating data using both molecular genetic methods and field and greenhouse experiments.  Many of these students have presented their results at conferences or have co-authored scientific publications.


My students and I investigate a broad array of questions in plant evolution and ecology.  In recent years, my research has taken three main directions.  First, I am working with a international team of scientists to explore how interactions between plants and insect pollinators affect the evolution of floral behavior in acacia trees and other selected plants within woodland savannah communities of Kenya.  Second, I am working with colleagues at IU South Bend, Butler University, and The Nature Conservancy to study how well newly restored prairies mimic the diversity and population dynamics found in native prairies of northern Indiana..  Third, I am studying the evolutionary history and population genetics of species in the legume genus Gleditsia and its near relatives, with emphasis on biogeographic connections between species on different continents, hybridization between species, and the propensity of certain species, such as the North American honeylocust (G. triacanthos), to become invasive when introduced into new habitats.  


Ruiz Guajardo, J. C., A. Schnabel. R. Ennos, S. Preuss, A. Otero-Arnaiz, and G. Stone. 2010. Landscape genetics of the key African acacia species Senegalia mellifera (Vahl)– the importance of the Kenyan Rift Valley. Molecular Ecology 19(23): 5126-5139.

Dolan R. W., D. L. Marr, and A. Schnabel.  2008.  Capturing genetic variation during ecological restorations: an example from Kankakee Sands in Indiana.  Restoration Ecology 16(3): 386-396.

Ruiz-Guajardo J.C., A. Otero-Arnaiz, T. Taylor, G. Stone, T. C. Glenn, N. A. Schable, J. T. Miller, S. Preuss,  and A. Schnabel.  2007.  Isolation of polymorphic microsatellite markers in the sub-Saharan tree, Acacia (Senegalia) mellifera (Fabacaeae: Mimosoideae)Molecular Ecoogy Notes 7(6): 1138-1140.

Otero-Arnaiz A,. A. Schnabel, T. C. Glenn, N. A. Schable, C. Hagen, and L. Ndong.  2005. Isolation and characterization of microsatellite markers in the East African tree, Acacia brevispica (Fabaceae: Mimosoideae).  Molecular Ecology Notes 5(2): 366-368.

Schnabel A. and K. V. Krutovskii.  2004.  Conservation genetics and evolutionary history of Gleditsia caspica:  inferences from allozyme diversity in populations from Azerbaijan.  Conservation Genetics 5(2): 195-204.

Schnabel A., P. E. McDonel, and J. F. Wendel.  2003.  Phylogenetic relationships in Gleditsia (Leguminosae) based on ITS sequences.  American Journal of Botany 90: 310-320.

Grens, A., D. Marr, and A. Schnabel.  2002.  Writing in the sciences.  In: Making Sense: Constructing Knowledge in the Arts and Sciences (eds. B. Coleman, R. Brittenham, S. Campbell, S. Girard), pp. 636-639.  Houghton Mifflin, Boston, MA.

Schnabel, A., and J. F. Wendel.  1998.  Cladistic biogeography of Gleditsia (Leguminosae) based on ndhF and rpl16 chloroplast gene sequences. American Journal of Botany 85: 1753-1765.

Schnabel, A.  1998.  Parentage analysis in plants:  mating sytems, gene flow, and relative fitness.  In: Advances in Molecular Ecology (ed. G. R. Carvalho), pp. 173-189.  IOS Press, Amsterdam.

Schnabel, A., P. Beerli, A. Estoup, and D. Hillis.  1998.  A guide to software packages for data analysis in molecular ecology.  In: Advances in Molecular Ecology (ed. G. R. Carvalho), pp. 291-303.  IOS Press, Amsterdam.

Schnabel, A., J. D. Nason, and J. L. Hamrick.  1998.  Understanding the population genetic structure of Gleditsia triacanthos L.: seed dispersal and variation in female reproductive success.  Molecular Ecology 7(7): 819-832.

Seelanan, T., A. Schnabel, and J. F. Wendel.  1997.  Congruence and consensus in the cotton tribe (Malvaceae).  Systematic Botany 22: 259-290.

Laushman, R. H., A. Schnabel, and J. L. Hamrick.  1996.  Electrophoretic evidence for tetrasomic inheritance in the dioecious tree, Maclura pomifera (Raf.) Schneid. Journal of Heredity 87: 469-473.

Schnabel, A., and J. L. Hamrick.  1995.  Understanding the population genetic structure of Gleditsia triacanthos L.:  The scale and pattern of pollen gene flow.  Evolution 49: 921-931.

Wendel, J. F., A. Schnabel, and T. Seelanan.  1995.  An unusual ribosomal DNA sequence from Gossypium gossypioides reveals ancient, cryptic, intergenomic introgression.  Molecular Phylogenetics and Evolution 4: 298-313.

Wendel, J. F., A. Schnabel, and T. Seelanan.  1995.  Bi-directional interlocus concerted evolution following allopolyploid speciation in cotton (Gossypium).  Proceedings of the National Academy of Sciences USA 92: 280-284.

Broyles, S. B., A. Schnabel, and R. Wyatt.  1994.  Evidence for long-distance pollen dispersal in milkweeds (Asclepias exaltata).  Evolution 48: 1032-1040.

Hamrick, J. L., A. F. Schnabel and P. V. Wells.  1994.  Distribution of genetic diversity within and among populations of Great Basin conifers.  In:  Natural History of the Colorado Plateau and Great Basin (eds. K. T. Harper, L. St. Clair, K. Thorne, and W. M. Hess), pp. 147-161.  University Press of Colorado, Niwot, CO.

Schnabel, A., J. L. Hamrick, and P. V. Wells.  1993.  Influence of Quaternary history on the population genetic structure of Douglas-fir (Pseudotsuga menziesii) in the Great Basin.  Canadian Journal of Forest Research 23: 1900-1906.

Chesser, R. K., O. E. Rhodes, Jr., D. Sugg, and A. Schnabel.  1993.  Effective sizes for subdivided populations.  Genetics 135: 1221-1232.

Schnabel, A., and M. A. Asmussen.  1992.  Comparative effects of pollen and seed migration on the cytonuclear structure of plant populations  II. Paternal cytoplasmic inheritance.  Genetics 132: 253-267.

Schnabel, A., R. H. Laushman, and J. L. Hamrick.  1991.  Comparative genetic structure of two co-occurring tree species, Maclura pomifera (Moraceae) and Gleditsia triacanthos  (Leguminosae).  Heredity 67: 357-364

Asmussen, M. A., and A. Schnabel.  1991.  Comparative effects of pollen and seed migration on the cytonuclear structure of plant populations  I. Maternal cytoplasmic inheritance.  Genetics 128: 639-654.

Schnabel, A., and J. L. Hamrick.  1990.  The organization of genetic diversity within and among populations of Gleditsia triacanthos L.  American Journal of Botany  77: 1060-1069.

Schnabel, A. and J. L. Hamrick.  1990.  Nonrandom associations between sex and 6-phosphogluconate dehydrogenase isozyme genotypes in Gleditsia triacanthos L. Journal of Heredity 81: 230-233.

Schnabel, A. and J. L. Hamrick.  1990.  Comparative analysis of population genetic structure in Quercus macrocarpa Michx. and Q. gambelii Nutt.  Systematic Botany 15: 240-251.

Surles, S. E., J. Arnold, A. Schnabel, J. L. Hamrick and B. C. Bongarten.  1990.  Genetic relatedness in open-pollinated families of two leguminous tree species, Robinia pseudoacacia L. and Gleditsia triacanthos L.  Theoretical and Applied Genetics 80: 49-56.

Schnabel, A. and M. A. Asmussen.  1989.  Definition and properties of disequilibria within nuclear-mitochondrial-chloroplast and other nuclear-dicytoplasmic systems.  Genetics 123: 199-215.

Ranker, T. A. and A. F. Schnabel.  1986.  Allozymic and morphological evidence for a progenitor-derivative species pair in Camassia (Liliaceae).  Systematic Botany 11: 433-445.

Hamrick, J. L. and A. Schnabel.  1985.  Understanding the genetic structure of plant populations:  Some old problems and a new approach.  In H. R. Gregorius (ed.), Population Genetics in Forestry.  Lecture Notes in Biomathematics, Vol. 60, pp. 50-70.  Springer-Verlag, Berlin.