The fish species Amatitlania nigrofasciata, convict cichlids, exhibit the behavior of serial monogamy. Dopamine has been linked to the success of pair bonding and monogamy. Dopaminergic (DA) neurons, the receptors of dopamine, are the reason the reward feeling of dopamine is felt by organisms. These neurons are housed in the Ventral Tegmental Area (VTA). The Wnt morphogen, which works through the Wnt pathway, has been previously shown to be a key player in the formation of the midbrain, the area where the VTA resides. This thesis delves into comparing gene expression related to the Wnt morphogen between convict cichlids and the polygamous control, D.rerio (zebrafish).

RNA probes were created to target mRNA that codes for specific proteins in the Wnt pathway, Wnt-1 and Fzd-1 in convict cichlids and zebrafish. In Situ Hybridization (ISH) using convict cichlid and zebrafish embryos was performed to distinguish gene expression between the two species. Whole-mount images of these embryos were taken to study the placement and concentration of the morphogen. Convict cichlids have been shown to have similar placement to zebrafish with Wnt-1, but convict cichlids show heterochrony with the development of Wnt-1. Fzd-1 placement and concentrations are different between convict cichlids and zebrafish. These first glimpses into the similarities and differences of gene expression may provide insight into the formation of the VTA and DA neurons.