Ph. D. 1995, University of Pennsylvania
Associate Professor of Biomedical Genetics and of Biology
Sex differences in the development and function of the C. elegans nervous system:
Research in the Portman lab centers on a general interest in understanding the biological basis for sex differences in development and behavior. Though this issue is of fundamental biological importance, large gaps remain in our mechanistic understanding of the connections between chromosomal sex and the multiple characteristics—particularly in the nervous system—that distinguish the sexes. These processes are likely to have central importance for the many neurological and mental health disorders that exhibit sex differences, including autism, anxiety and a variety of neurodegenerative diseases.
The fundamental importance of sex, still an area of great interest for evolutionary biologists, has enabled sex-specific selective pressures to shape many diverse aspects of animal development and physiology. These go far beyond simple differences in gonads and genitalia: virtually every organ system in mammals is altered, presumably in an adaptive way, to suit each sex's specific demands. Traditionally, these sex differences have been thought to stem entirely from sex-specific hormonal signals broadcast by the gonads. In this model, the only significant intersection between sex chromosome karyotype and developmental regulation is in the gonad itself, where sex determination mechanisms act to guide the differentiation of the gonad primordium. However, a series of compelling recent findings in birds and mammals have challenged this view, clearly demonstrating that sexual karyotype can act independently of gonadal steroids, particularly in the CNS. Together, these findings have called for a fundamental revision of the "hormone-only" view of sexual differentiation. Moreover, they support the intriguing idea that a primary genetic sex-determination pathway--that is, the translation of cellular sex-chromosome status to the sexual phenotype of the cell--acts not only in the vertebrate gonad but also in the soma. According to this model, sexual dimorphism would emerge from the combined influence of hormones and cell-autonomous sex determination, with some characteristics relying more heavily on one or the other of these two inputs.
The extraordinary resolution with which biological mechanisms can be understood in the nematode C. elegans makes it an ideal system in which to explore the means by which cellular sex regulates a host of developmental and functional changes throughout the body, particularly in the nervous system. As C. elegans is arguably the only model whose tractability extends across the molecular, cellular, circuit and systems levels, fundamental insights into the way that neural development, neurophysiology and behavior depend on cellular sex are likely to emerge from addressing these questions in this unique system.
Miller RM and Portman DS. (2011) The Wnt/ß-catenin asymmetry pathway patterns the atonal ortholog lin-32 to diversify cell fate in a Caenorhabditis elegans sensory lineage. J. Neurosci, in press.
R.M. Miller and D.S. Portman. (2010) A latent capacity of the C. elegans polycystins to disrupt sensory transduction is repressed by the single-pass ciliary membrane protein CWP-5. Disease Models and Mechanisms 3:441-450. View article in PubMed
D.D. Hurd, R.M. Miller, L. Núñez and D.S. Portman. (2010) Specific α- and β-tubulin isotypes optimize the functions of C. elegans sensory cilia. Genetics 185:883-896. View article in PubMed
Mason DA, Rabinowitz JS and Portman DS (2008) dmd-3, a doublesex-related gene regulated by tra-1, governs sex-specific morphogenesis in C. elegans. Development 135: 2373-82. View article in PubMed.
Lee KH and Portman DS (2007) Neural sex modifies the function of a C. elegans sensory circuit. Curr Biol 17:1858-63.
Portman DS (2007) Genetic control of sex differences in C. elegans neurobiology and behavior. Adv Genet 59:1-37. View article in PubMed.
Graduate Program Affiliations
- Ph.D. in Genetics, Genomics and Development (GGD)
- Biochemistry, Molecular and Cell Biology (BMCB)
- Neuroscience (NS)
Douglas S. Portman, Ph.D.
University of Rochester
601 Elmwood Ave., Box 645
Rochester, NY 14642
Office: MRB 2-9641
Reneé Miller, Ph.D.
Edward Vuong M.D./Ph.D. student
|Daryl Hurd, Ph.D.
Adjunct Assistant Professor
|Deborah Ryan, Ph.D. Postdoctoral Research Associate|
|Jessica Bennett Technician|