GENOMIC IMPRINTING IN Drosophila melanogaster: EPIGENETIC REGULATION OF THE Dp(1;f)LJ9 IMPRINTED DOMAIN

Abstract

Genomic imprinting is an epigenetic phenomenon whereby the expression of a gene, chromosomal region, or entire chromosome, depends on the sex of the transmitting parent. Imprinting results in an otherwise fully functional gene being transcriptionally silenced when transmitted by one parent, yet the same gene, with identical DNA sequence, is active when transmitted by the other. Thus, the gene retains an imprint or “memory” of its genetic history, which is reversible and reset each successive generation by passage through the germline. Within this thesis, I present my findings that show genomic imprinting in Drosophila is regulated by distinct epigenetic mechanisms at different stages of embryogenesis, suggesting the requirement of a transitional stage to stabilize the imprint between establishment in the germline and maintenance in the soma. I futher show that Drosophila utilize epigenetic mechanisms that are involved in regulating genomic imprinting in mammals and plants, such as DNA methylation, histone modification, antisense RNA, and chromatin insulators. These findings demonstrate convergence of the epigenetic mechanisms that regulate genomic imprinting in diverse organisms.