title: Sexually dimorphic gene expression in the lateral eyes of Euphilomedes carcharodonta (Ostracoda, Pancrustacea).
abstract: BACKGROUND
  The evolution and development of sexual dimorphism illuminates a central question in biology: How do similar genomes produce different phenotypes? In an XX/XO system especially the state of a sexually dimorphic trait is determined by differences in gene expression, as there are no additional genetic loci in either sex. Here, we examine the XX/XO ostracod crustacean species Euphilomedes carcharodonta. This species exhibits radical sexual dimorphism of their lateral eyes, females have only a tiny simple lateral eye while males have elaborate ommatidial eyes.
  
  
  RESULTS
  We find that males express three of nine eye-development gene homologs at significantly higher levels during juvenile eye development, compared to females. We also find that most eye-development genes examined are pleiotropic, with high expression levels during embryonic development as well as during juvenile eye development. Later, in adults, we find that phototransduction genes are expressed at higher levels in males than in females, as we might expect when comparing ommatidial to simple eyes.
  
  
  CONCLUSIONS
  We show here that expression changes of a handful of developmental genes may underlie the radical difference in a dimorphic character. This work gives an important point of comparison for studying eye evolution and development in the Pancrustacea.
authors.affiliation: Department of Biological Sciences, University of the Pacific, Stockton, CA USA ; Stritch School of Medicine, Loyola University, Chicago, IL USA.
authors.forename: Andrea
authors.initials: A
authors.lastname: Sajuthi
authors.affiliation: Department of Biological Sciences, University of the Pacific, Stockton, CA USA ; Dugoni School of Dentistry, University of the Pacific, San Francisco, CA USA.
authors.forename: Brenna
authors.initials: B
authors.lastname: Carrillo-Zazueta
authors.affiliation: Department of Biological Sciences, University of the Pacific, Stockton, CA USA.
authors.forename: Briana
authors.initials: B
authors.lastname: Hu
authors.affiliation: Department of Biological Sciences, University of the Pacific, Stockton, CA USA ; Thomas J. Long School of Pharmacy and Health Sciences, University of the Pacific, Stockton, CA USA.
authors.forename: Anita
authors.initials: A
authors.lastname: Wang
authors.affiliation: Department of Biological Sciences, University of the Pacific, Stockton, CA USA ; Thomas J. Long School of Pharmacy and Health Sciences, University of the Pacific, Stockton, CA USA.
authors.forename: Logan
authors.initials: L
authors.lastname: Brodnansky
authors.affiliation: Department of Biological Sciences, University of the Pacific, Stockton, CA USA.
authors.forename: John
authors.initials: J
authors.lastname: Mayberry
authors.affiliation: Department of Biological Sciences, University of the Pacific, Stockton, CA USA.
authors.forename: Ajna S
authors.initials: AS
authors.lastname: Rivera
keywords: Development; Evolution; Expression; Eye; Ostracod; Pancrustacean; Sexual dimorphism