Meeting Abstract
Many non-mammalian organisms lack sex chromosomes and sex is instead determined through genome-by-environment interactions experienced during discrete developmental periods. Temperature-dependent sex determination provides a unique window through which to examine how external stimuli are integrated into physiological responses that shape phenotypic diversity in terms of both inter- and intra-sexual variation. Yet our understanding of these fundamental processes has historically been shaped by experimental studies employing constant incubation temperatures that do not accurately reflect the environments experienced in nature. In order to understand the scope of thermal variation experienced during development by the American alligator, this project uses field data to characterize the nest thermal dynamics of 70 alligator nests monitored over the course of seven years at two geographically distinct sites. These field data demonstrate the variable nature of the thermal environment experienced during development. Interestingly, the majority of alligator embryos experience both male- and female-promoting temperatures during the thermosensitive period in development, frequently within a daily cycle. These findings form the basis for current experiments probing the mechanisms by which these opposing environmental cues are integrated into concerted developmental programs and their consequences for later reproductive function.
