I am an evolutionary ecologist, and my research involves studies of:

• Comparative Evolutionary Genomics
• Ecological Genomics
• Genome Evolution
• Evolutionary Developmental Biology
• Sex Determination
• Population and Ecological Genetics
• Life History Evolution
• Herpetology
• Tropical Biology
• Conservation

I am a fourth year Ph.D. student. I have experience in conservation and life history of turtles. I am interested in understanding the causes and consequences of phenotypic evolution. My current work focuses on phenotypic plasticity of body growth in Podocnemis expansa and Chelydra serpentina and its effect on sexual size dimorphism and Rensch's rule in turtles. My work is funded by the National Science Foundation (DEB 0808047) and the Turtle Conservation Fund, to N. Valenzuela (PI) and C Ceballos (CoPI).

I am a third year Ph.D. student. I am working on sex chromosome evolution and comparative gene mapping in turtles.

My work is funded by the National Science Foundation (MCB 0815354 to N. Valenzuela [PI] and S.V. Edwards [CoPI, Harvard University].

 

2008. Martinez, P., Ezaz T., Valenzuela, N., Georges, A., and Graves J.A.M. An XX/XY heteromorphic sex chromosome system in the Australian chelid turtle Emydura macquarii, a new piece in the puzzle of sex chromosome evolution in turtles. Chromosome Research: 16(6): 815-825. DOI 10.1007/s10577-008-1228-4.

I am an NSF postdoctoral fellow. I am very interested in the ecology, life history evolution and conservation of freshwater turtles in the Neotropics. I am working on the metapopulation genetic analysis of Podocnemis unifilis turtles in South America.

My work is funded by the National Science Foundation (DBI 0511958 to T. Excalona), and the Scott Neotropical Fund from the Cleveland Zoo (to N. Valenzuela [PI] and T. Escalona [CoPI]).

Tibisay’s Website

2009. Escalona, T., Engstrom T.N., Hernandez O.E., Bock B.C., Vogt R.C. and Valenzuela N. Population genetics of the endangered South American freshwater turtle, Podocnemis unifilis, inferred from microsatellite DNA data. Conservation Genetics. DOI 10.1007/s10592-008-9746-3

I am a postdoctoral fellow. My previous work focused on the temporal changes in population genetic dynamics of the eastern collared lizard, Crotaphytus collaris collaris, in response to forest fire management. I am now working on an eco-genomics project to study the effect of fluctuating temperature on the expression of genes involved in gonadogenesis in TSD turtles.

My work is funded by the National Science Foundation (IOS 0743284 to N. Valenzuela).

Jennifer's Website

I completed my Ph.D. in 2008. My work focused on the ecological processes responsible for species co-ocurrence patterns in two species of Plethodon salamanders. I was co-advised by Dean Adams.

Postdoctoral associate. Taka worked on the molecular evolution of sex related genes across reptiles and other vertebrates that possess contrasting sex determining mechanisms, in order to shed light on the evolution of sex determination.

I graduated from the Biology program at ISU. For my honors thesis I worked on a project aimed to compare the expression profiles of sex genes (genes involved in sex differentiation) between turtles with temperature-dependent sex determination (Chrysemys picta) and turtles with genotypic sex determination (Apalone mutica) incubated under identical conditions. We were searching for key differences to understand the mechanics of both sex determining systems.

As an undergraduate, I worked on population genetics of Podocnemis unifilis turtles from Colombia and Peru, and on maternal-effect genes related to sex differentiation in Chrysemys picta turtles from North America. I completed my Master’s in 2008 in the EEB program at ISU working on Wildlife Management with Dr. Sue Fairbanks.

I was a Ph.D. rotation student. I am interested in the evolution of sex determination.

 

I was a Ph.D. rotation student from the Bioinformatics & Computational Biology program.

I was a MSc rotation student from the Interdepartmental Genetics program.