Turk Rhen
 
Assistant Professor
Department of Biology
University of North Dakota
Grand Forks,
ND 58202-9019
E-mail: turk.rhen@und.nodak.edu
Phone: (701) 777-4667
Fax: (701) 777-2623
Education and Training
Postdoctoral Fellow 2000-2003, National Institute of Environmental Health Sciences
Ph.D. 2000, University of Texas-Austin
M.S. 1993, University of North Dakota
B.S. 1991, University of North Dakota
Research Interests
I am fascinated by the evolution of gender differences. Ghiselin (1988) aptly wrote, "Gender means the differentiation into males, females, and such alternatives as hermaphrodites. It also includes the differences between sperm and eggs. Such differences are important because they create the circumstances that make sex a
puzzle." Ghiselin, M.T. 1988. The evolution of sex: a history of competing points of view. Pp. 7-23. In The Evolution of Sex . Ed. R.E. Michod and B.R. Levin. Sinauer Associates Inc., Sunderland, MA. Yet, despite the central role gender plays in biology, we are only beginning to understand how diverse mechanisms of gender differentiation have evolved. These mechanisms include sex-linkage and sex chromosomes, sex-limited expression of genes on the autosomes, and environmental influences on gender differentiation. It is here that my interests reside, at the junction between the mechanistic bases and ultimate causes of gender differences in the brain and behavior, physiology, morphology, and in life history patterns.
In accord with these broad interests, my research has examined both theoretical and empirical aspects of sex determination, sexual differentiation, and reproductive biology. I have used diverse vertebrates as model organisms and embrace the comparative method in biology. The most recent application of this methodology is seen in the burgeoning field of comparative genomics. My current research focuses on experiments designed to identify evolutionarily conserved, as well as unique, genes involved in sex determination in vertebrates. Additional experiments will test the hypothesis that synthetic chemicals act as endocrine disruptors to alter the expression of these key developmental genes and produce abnormalities in the structure and/or function of the gonads.
Selected Publications
Rhen, T., S. Grissom, C. Afshari, and J.A. Cidlowski. 2003. Dexamethasone blocks the biological effects of 17 b -estradiol in the rat uterus without antagonizing its global genomic actions. FASEB Journal 17: 1849-1870.
Rhen, T., and D. Crews. 2002. Variation in reproductive behavior within a sex: neural systems and endocrine activation. Journal of Neuroendocrinology 14: 517-532.
Rhen, T., and D. Crews. 2001. Distribution of androgen and estrogen receptor mRNA in the brain and reproductive tissues of the leopard gecko, Eublepharis macularius . Journal of Comparative Neurology 437: 385-397.
Willingham, E., T. Rhen, J.T. Sakata, and D. Crews. 2000. Embryonic treatment with xenobiotics disrupts steroid hormone profiles in hatchling red-eared slider turtles ( Trachemys scripta elegans ). Environmental Health Perspectives 108: 329-332.
Rhen, T. 2000. Sex-limited mutations and the evolution of sexual dimorphism. Evolution 54: 37-43.
Rhen, T., and D. Crews. 1999. Embryonic temperature and gonadal sex organize male-typical sexual and aggressive behavior in a lizard with temperature-dependent sex determination. Endocrinology 140: 4501-4508.
Rhen, T. and J.W. Lang. 1998. Among-family variation for environmental sex determination in reptiles. Evolution 52: 1514-1520.
Rhen, T. and J.W. Lang. 1995. Phenotypic plasticity in the common snapping turtle: effects of incubation temperature, clutch, and their interaction. American Naturalist 146: 726-747.
Rhen, T. and J.W. Lang. 1994. Temperature-dependent sex determination in the snapping turtle:manipulation of the embryonic sex steroid environment. General and Comparative Endocrinology 96: 243-254.
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