A Multifaceted Approach to Drosophila Eye and Head Development: Genetic, Transcriptomic, and Phenotypic Analyses

Head and eye development in Drosophila melanogaster involves intricate genetic regulation coordinated across spatial and temporal scales. In this study, we employed an integrative framework combining genome-wide association studies (GWAS), single-cell RNA sequencing (scRNA seq), and morphological analysis to investigate the genetic basis of natural variation in eye and head morphology. GWAS identified 230 single-nucleotide polymorphisms (SNP) associated with eye area and head width variation, including bru1, a gene not previously linked to eye development. To explore expression profiles of candidate genes, we analyzed publicly available single-cell transcriptomic data (GSE235110) from the larval eye-antennal disc. Known regulators such as tkv, Svil, CG42747, and CG42389 were enriched in photoreceptor precursor cells. In contrast, bru1 exhibited no detectable expression at the larval stage, suggesting a temporally restricted role, possibly during pupal remodeling. Morphological characterization of bru1 confirmed its contribution to eye area, providing functional validation for its developmental relevance. These findings demonstrate the power of integrating genomic, transcriptomic, and phenotypic analyses to uncover novel regulators of organogenesis. This approach enhances our understanding of genetic architecture underlying complex morphological traits such as head and eye development in Drosophila melanogaster.