EvSex Presentation - Nicole Valenzuela

Environmental vs Genotypic Sex Determination - Nicole Valenzuela

Department of Ecology, Evolution and Organismal Biology 
Iowa State University, Ames USA
Environmental, genetic, and epigenetic regulation of sex determination and the ecological drivers of its intriguing evolutionary history

Why do organisms vary so remarkably in the ways they produce males and females? Sexually-reproducing organisms employ diverse mechanisms to produce males and females, ranging from systems under strict genetic control (GSD) [such as highly dimorphic or undifferentiated sex chromosomes (XY, ZW)], to systems under strict environmental control dependent [such as those dependent on temperature (TSD) as is commonly found in reptiles and fish], or both. The evolution of this diversity has defied scientific explanation and to answer this question it is essential that we understand its ecological context, mechanics, and evolutionary patterns. These talks will showcase research conducted to illuminate the molecular basis of TSD in turtles and how it differs from GSD, as well as research on the causes and consequences of chromosome evolution. This includes studies of the genetic and epigenetic regulation of turtle sexual development, the evolution of sex chromosomes and the genes they contain, with further emphasis during the public lecture on the evolution of turtle genome organization into chromosomes and its association with climate change, and the role of life history traits on the evolution of sex determination and diversification.