DNA Methylation Changes in a Gene-Specific Manner in Different Developmental Stages of Drosophila melanogaster

Although genomic DNA of Drosophila melanogaster has been shown to contain little cytosine methylation, the distribution of this genome-wide methylation patterns in different life stages remains to be elucidated. We have developed an immunochemical method using cDNA microarray to assess methylation. In the present work, this methylation microarray method was employed to identify DNA methylation in and around the genes in different life stages of D. melanogaster. This led to the identification of methylated genes in three stages of D. melanogaster, viz. embryo, pupa and adult. It is noteworthy that there was differential methylation in genes in different life cycle stages. Remarkably, a few functional annotation clusters showed negative correlation between transcription of a particular gene and its methylation status. In this analysis, some of the genes attributed to characteristic biological processes of particular life stage in D. melanogaster were found to be methylated in other life stages. Our analysis while providing a methylation map also suggests that gene-specific DNA methylation is altered during the life cycle stages of D. melanogaster.