The Sower laboratory focuses on two species of fish, lampreys and hagfish, which are the only two living representatives of the oldest lineage of vertebrates. The overall objective of my current research has been to test the global hypothesis that the reproductive physiology of the lamprey is controlled at the hypothalamic-pituitary-gonadal axis by a gonadotropin releasing-hormone (GnRH)/receptor and glycoprotein hormone/glycoprotein hormone receptor system homologous to the system acting in gnathostomes.