DNA of Drosophila melanogaster contains 5-methylcytosine

Abstract

It is commonly accepted that the DNA of Drosophila melanogaster does not contain 5‐methylcytosine, which is essential in the development of most eukaryotes. We have developed a new, highly specific and sensitive assay to detect the presence of 5‐methylcytosine in genomic DNA. The DNA is degraded to nucleosides, 5‐methylcytosine purified by HPLC and, for detection by 1D‐ and 2D‐TLC, radiolabeled using deoxynucleoside kinase and [γ‐³²P]ATP. Using this assay, we show here that 5‐methylcytosine occurs in the DNA of D.melanogaster at a level of ∼1 in 1000–2000 cytosine residues in adult flies. DNA methylation is detectable in all stages of D.melanogaster development.