Climate Science Program

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Nicole Valenzuela

Assistant Professor


Office: 239 Bessey Hall

Phone: 515-294-1285






Department: Ecology, Evolution, and Organismal Biology

Research Interests:Ecology and evolution of sex determining mechanisms, molecular ecology, life history, and conservation of turtles.

Brief description of current research:

Dr. Valenzuela is an evolutionary ecologist interested in comparative evolutionary genomics related to the evolution of developmental pathways, particularly those that underlie the development of the sexual phenotype. Some of her research focuses on understanding why sex is determined by nest temperature in many reptiles by deciphering how such mechanism works at the molecular level and how it differs from genetically-controlled systems in closely related species. To answer these questions, Dr. Valenzuela is undertaking an NSF-funded project to elucidate the effect that naturally-fluctuating temperature has on the expression of genes involved in the formation of ovaries and testis in turtles with temperature-dependent sex determination, in order to understand how males and females are produced in nature, and how these thermosensitive species may respond to short- and long-term climate change.

Recent publications:

Valenzuela, N. 2008. Sexual development and the evolution of sex determination. Sexual Development (in press).

Valenzuela, N. 2008. Relic Thermosensitive gene expression in a turtle with genotypic sex determination. Evolution 62-1: 234-240.

Valenzuela, N. and Shikano T. 2007. Embryological ontogeny of Aromatase gene expression in Chrysemys picta and Apalone mutica turtles: comparative patterns within and across temperature-dependent and genotypic sex-determining mechanisms. Development, Genes and Evolution 217: 55–62.

Valenzuela, N., LeClere A., and Shikano T. 2006. Comparative expression of steroidogenic factor 1 in Chrysemys picta and Apalone mutica turtles with environmental and genotypic sex determination. Evolution and Development 8 (5): 424-432