Abstract
BackgroundThe factors determining sex are diverse in vertebrates and especially so in teleost fishes. Only a handful of master sex-determining genes have been identified, however great efforts have been undertaken to characterize the subsequent genetic network of sex differentiation in various organisms. East African cichlids offer an ideal model system to study the complexity of sexual development, since many different sex-determining mechanisms occur in closely related species of this fish family. Here, we investigated the sex-determining system and gene expression profiles during male development of Astatotilapia burtoni, a member of the rapidly radiating and exceptionally species-rich haplochromine lineage.ResultsCrossing experiments with hormonally sex-reversed fish provided evidence for an XX-XY sex determination system in A. burtoni. Resultant all-male broods were used to assess gene expression patterns throughout development of a set of candidate genes, previously characterized in adult cichlids only.ConclusionsWe could identify the onset of gonad sexual differentiation at 11–12 dpf. The expression profiles identified wnt4B and wt1A as the earliest gonad markers in A. burtoni. Furthermore we identified late testis genes (cyp19a1A, gsdf, dmrt1 and gata4), and brain markers (ctnnb1A, ctnnb1B, dax1A, foxl2, foxl3, nanos1A, nanos1B, rspo1, sf-1, sox9A and sox9B).Electronic supplementary materialThe online version of this article (doi:10.1186/s12863-014-0140-5) contains supplementary material, which is available to authorized users.
Highlights
The factors determining sex are diverse in vertebrates and especially so in teleost fishes
Making use of candidate genes expressed in brain and gonad tissue of adult A. burtoni [11], we studied changes in gene expression throughout male sexual development
Generating all-male broods in A. burtoni Sexual development in fish is plastic and sex reversal can be induced in a variety of species even after reaching sexual maturity [40]
Summary
The factors determining sex are diverse in vertebrates and especially so in teleost fishes. Six master sex-determining genes have been identified in teleosts, namely dmy/dmrt1bY in Oryzias latipes and O. curvinotus [3,4], gsdfY in O. luzonensis [5], sox in O. dancena [6], amhy in Odontesthes hatcheri [7], amhr in Takifugu rubripes [8] and sdY in Oncorhynchus mykiss and several other salmonids [9,10] In addition to this variation in the initial regulators, we and others could show recently that the subsequent genetic steps of sex differentiation are not conserved in fishes, Master sex-determining genes are thought to be expressed early in development, marking the initial time point of the sexual development cascade. Expression studies on several fish sex determination genes covering the development from embryo to adults are lacking, and in mammals, the sex-determining gene sry is expressed in adult testis of mouse and rat [14,15]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
