Heule, Corina. The genetics of sexual development in East African cichlid fishes. 2015, PhD Thesis, University of Basel, Faculty of Science.
Official URL: http://edoc.unibas.ch/diss/DissB_11244
East African cichlid fishes are extremely diverse in terms of ecology, morphology and breeding behavior and therefore represent a prime model system in evolutionary biology in general, and in the study of sexual development in particular. Several sex determination systems have been described, which differ sometimes even between closely related species in this fish family.
In my thesis, I investigated a set of candidate genes for sexual development in cichlids. More specifically, we studied these genes in adult cichlid species and in one of them also during early male development. Differential gene expression patterns, measured in brain and gonad tissue, were observed between cichlid lineages and within the same species over time. One striking case is the shift in gene expression of the aromatase cyp19a1. In vertebrates, and in all teleosts investigated so far, cyp19a1A and cyp19a1B are expressed in the ovaries and the brain, respectively. In the species rich and extremely diverse haplochromine lineage, we found an overexpression of cyp19a1B in the testis. In another study, we show that Astatotilapia burtoni, a member haplochromine lineage, most likely has an XX-XY sex determination system. Making use of hormonally sex-reversed fish and subsequent crossing experiments, we establish all-male broods, which offered an ideal platform to investigate gene expression of early testis and brain genes. In addition, we identified several promising candidates for genetic sex determiners in this species.
|Committee Members:||Mank, Judith|
|Faculties and Departments:||05 Faculty of Science > Departement Umweltwissenschaften > Zoologisches Institut > Evolutionary Biology (Salzburger)|
|Bibsysno:||Link to catalogue|
|Number of Pages:||88 S.|
|Last Modified:||30 Jun 2016 10:57|
|Deposited On:||12 Jun 2015 08:26|
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