University of Michigan
Department of Ecology and Evolutionary Biology

Dr. Nicole Valenzuela, Associate Professor, Department of Ecology, Evolution, and Organismal Biology, Iowa State University

Sponsored by the University of Michigan Museum of Zoology Donald W. Tinkle Memorial Fund

Abstract
Why do organisms vary so remarkably in the ways they produce males and females? The evolution of sex-determining mechanisms (SDM) is marked by repeated transitions between systems that differ in their level of phenotypic plasticity and developmental canalization. Reptiles are an ideal group to study the driving forces and mechanisms underlying these evolutionary transitions as they display a wide diversity of SDM that encompass temperature-dependent sex determination (TSD) and genotypic sex determination (GSD) with either male (XY) or female (ZW) heterogamety.

Through a series of complementary studies, my lab is shedding light on how genomic structure and genome function affect the development and evolution of phenotypes, and the role that the environment plays in these processes at different time scales. Indeed, the level of phenotypic plasticity and genome organization themselves are driven by biotic factors such as sexual selection and sexual conflict, and abiotic influences such as thermal disturbances at contemporary (e.g. daily/seasonal/annual) and evolutionary (e.g. climate change over generations or millions of years) time scales.

In particular, I will highlight some of our projects through which we attempt to understand the evolution of the SDM and the gene regulatory networks underlying them; to discover the molecular changes that render TSD susceptible to temperature; to decipher how males and females are produced in nature and what is the evolutionary potential of TSD in the face of climate change; and to characterize the genomic rearrangements responsible for the evolution of sex chromosomes and diploid number.

Host: Lacey Knowles

Coffee and cookies served at 4 p.m.