Presenter: Andrew Delapaz, Biology
Poster: A-6
Mentor: Braedan McCluskey, Biology
Out of the nearly 60,000 species of known vertebrates, fish comprise nearly half of the group. Natural selection has created the spectrum of sizes, shapes, and colors seen in fish. However, the developmental mechanisms underlying these differences are still unknown. The zebrafish (Danio rerio) is a common model for development and genetics. Our specific purpose is to understand differences in anatomical structure development between zebrafish and related species. The sensory “whiskers” found on fish, also known as barbels, differ greatly within this genus and therefore are ideal to study. To investigate the genetics behind barbel development in Danio, we measured and compared barbel size and number in different species and hybrids between these species. These hybrids can be used to determine if a characteristic is inherited in a dominant or additive fashion. The species we used were zebrafish (D. rerio), and dwarf zebrafish (D. nigrofasciatus). We chose these species because in addition to clear differences in body size, D. rerio has two pairs of barbels, while D. nigrofasciatus has only one. The hybrids obtained from crossing these species had a single set of barbels, which were intermediate in length compared to the two parent species. These data indicate that barbel length and number are not determined by the same mechanism. By further researching barbels and other traits among this genus, we can deepen our understanding of how species diversity of vertebrates evolves.