Meeting Abstract

P2.142  Thursday, Jan. 5  The Medullary Rest: A Naturally Occurring Intersex Region of American Alligator Ovary BOTTERI, N.L.*; MOORE, B.C.; ALBERGOTTI, L.C.; HAMLIN, H.J.; LAWLER, A.N.; MATHAVAN, K.; GUILLETTE JR., L.J.; University of Florida; Louisiana Tech University; University of Florida; University of Maine; University of Miami; University of Massachusetts Amherst; Medical University of South Carolina nbotteri@ufl.edu

In the American alligator, temperature dependent sex determination (TSD) directs gonadal differentiation and is characterized as being an absolute process, producing either an ovary or a testis. However, in depth histological investigation of the alligator ovary reveals a naturally occurring intersex region. The “medullary rest”, first described by T.R. Forbes in the 1930s, is an atypical ovarian region lacking cortical and medullary morphology characteristic of an alligator ovary. In contrast, the medullary rest is comprised of disorganized tubule-like structures containing presumptive germ cells, reminiscent of testicular tissue. Here, we further Forbes’ investigation of this region by using differential histological stains to show that the medullary rest is a dynamic region, maturing throughout ontogeny, demonstrating both ovarian and testicular characteristics. Current investigations seek to quantify gene expression of adult alligator medullary rest using sexually dimorphic molecular markers previously described by our group. Future endeavors will quantify the potential hormonal responsiveness of the medullary rest using both histological and molecular endpoints. Characterization of the medullary rest is essential in order to ascertain potential ramifications for reproduction.