Long intergenic non-coding RNAs (lincRNAs) are a recently discovered group of transcripts that have no protein-coding capacity. Although they play diverse and important roles in the biology of complex organisms, almost nothing is known of their origin and evolution. The goal of this project is to use next generation RNA sequencing technology (RNA-Seq) and the vast genomic resources of the fruit fly Drosophila to characterize the forces that underlie lincRNA sequence and expression evolution. Analyses of variation in pure species cannot explain how the regulation of lincRNA expression evolves, but analyses of misexpression in hybrids provides insight into how diverse evolutionary processes shape the regulatory process. Thus, the specific goal of this dissertation improvement grant is to analyze the evolution of lincRNA regulation using RNA-Seq in D. pseudoobscura/D. persimilis hybrids. Specific aims are (1) to identify the mode of inheritance of lincRNA expression, (2) identify whether lincRNA regulatory divergence occurs through cis or trans changes, and (3) identify whether lincRNAs may underlie hybrid incompatibilities.
This work will be the most comprehensive analysis of lincRNA evolution to date and the first to examine lincRNA regulatory evolution in closely related species via hybrids. It will underscore the importance of an understudied class of genes that deviates from the central dogma of biology. This grant will support the training of both a doctoral student and multiple undergraduates as well as provide a summer research experience for a local high school student or teacher from the University of Maryland's Minority Student Pipeline. The knowledge gleaned from this work will be disseminated widely, both in national presentations and in print. Understanding the evolution of gene regulatory systems provides important insights into the relationship between genotype and phenotype, which ultimately underlies our understanding of disease and the improvement of agricultural crops.
