NSF Award
2211833
Two goals of scientific inquiry are to understand how traits develop and evolve. These goals have proven difficult to reach for animal species with vast genomes and ones that undergo complex developmental processes. This project will use the pattern of male melanic abdomen pigmentation that develops for the fruit fly species D. melanogaster as a model for a trait’s development, and related species with differing pigmentation as models to understand how male pigmentation originated and diversified. In order to determine which gene’s use or genes’ uses have changed in route to this pigmentation diversity, the network of genes responsible for melanogaster pigmentation will be studied in species with the ancestral (D. willistoni) and modified (D. auraria) pattern of male pigmentation. For genes with differing uses, approaches will be utilized to find and characterize the parts of genes responsible for their variation. The importance of these modified gene parts will be tested by engineering melanogaster sequences into the genomes of these two less well-studied species. Collectively, this project will push the limits of genetic investigation in model and emerging-model species, resulting in one of the most insightful genetic characterizations of an evolving animal trait. This project will result in numerous broader impacts, such as the refinement of bioinformatic and online resources for genetics research, training of diverse personnel in genetics and related disciplines, and hastening scientific progress by the creation, organization, and hosting of a virtual meeting for scientists with a shared interest on the genetics of development and evolution. <br/><br/>Animal morphology develops through the operation of Gene Regulatory Networks (GRNs) that involve a plethora of trans-regulators, transcription factors and signaling pathways, which control the spatial, temporal, and even sex-specific patterns of trait-building realizator gene expression. These patterns of gene expression emerge from GRN transcription factors interacting with binding sites in the cis-regulatory elements (CREs) of their direct target genes. Since many trans-regulators and realizator genes are older than the traits they regulate, trait evolution occurs through changes in the uses of these ancestral genes. This project’s overarching goal is to understand how a trait emerged and was modified by changes to a GRN’s trans-regulators and realizator genes. The evolution of a GRN for a rapidly evolving trait present in an experimentally tractable animal model species, and closely-related emerging model species will be examined. The proposed studies will focus on how the male-specific pattern of abdominal pigmentation emerged in the fruit fly lineage of D. melanogaster and how it was modified in the montium lineage. In the first Aim, the breadth of trans-regulators in the D. melanogaster GRN will be mapped, and determine which of these genes have conserved or evolved expressions in species with the ancestral and modified trait phenotypes. The second aim will determine how trans-regulator and realizator gene expressions evolved through CRE evolution. The third aim will directly test the phenotypic consequences of GRN modifications through genetic engineering performed in emerging model species.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
