Meeting Abstract
Neoteleosts exhibit a stunning array of diversity in morphology and behavior that often matches their preferred feeding mode. For instance, benthic fish that remove food from the substrate tend to differ in consistent and predictable ways from pelagic fish that hunt mobile prey in the water column. Many fish lineages vary along this axis comprised of ecological, behavioral, and morphological variables. Much of the literature focuses on the differences between benthic and pelagic head and trophic structures; however, significant changes also occur to body shape and fin morphology. These differences likely evolve in response to distinct locomotive demands which are associated with various foraging tactics. Here we focus on natural variation in the development of fin morphology among several species of African cichlids, including the close ecological competitors Labeotropheus fuelleborni (LF) and Tropheops sp. redcheek (TRC). We next describe variation within an F2 population of LF x TRC hybrids, and use that population to perform a quantitative trait loci analysis seeking the genetic factors that influence fin shape and its underlying musculature. We show that the genotype-phenotype map for fin and body shape is distinct from that for head/jaw shape, which suggests that these traits coevolve due to common selective pressures, not pleiotropy. We also present a notable candidate gene, wnt7aa, which may underlie variation in the number of bony fin rays that support the pectoral fin. We describe variation in the expression of wnt7aa across species, and use small molecules to modulate Wnt expression during fin development. Our work seeks to better understand the fundamental interplay between genetics, development, and morphology during this textbook adaptive radiation.
