Genomic and Hormonal Components of Altered Developmental Pathways in the Annual Killifish, Austrofundulus limnaeus

Abstract

The annual killifish, Austrofundulus limnaeus, may enter embryonic diapause at three distinct points of development, termed diapause I, II, and III. Previous studies suggest a role for steroid hormones in the regulation of diapause in annual killifish.This study concerns the hormonal and genomic components involved in the developmental decision to enter or escape diapause II from both a maternal and embryonic perspective. Steroid hormone levels were measured in tissues isolated from adult female fish that were producing either high or low proportions of escape embryos. Levels of steroid hormones were also measured in new fertilized embryos that were known to be on either an escape or diapausing developmental trajectory. In

Transcriptomic Regulation of Alternative Phenotypic Trajectories in Embryos of the Annual Killifish <i>Austrofundulus limnaeus</i>

“…Additionally, exposure to high amounts of exogenous estrogen and cortisol can cause embryos to shift from a diapausing to an escape developmental trajectory (Pri-Tal, Blue et al 2011). A preliminary microarray transcriptome analysis of ovarian tissue from females producing exclusively escape embryos identified a number of differentially expressed genes involved in steroid hormone signaling, such as nuclear receptor and steroid metabolic enzymes that may contribute to phenotypic regulation (Pri-Tal 2010). Steroid hormones strongly influence organismal physiology and can dictate the developmental outcomes of vertebrates regarding metabolism, sexual dimorphism, and reproduction.…”