Survey of DNA polymerase activity during the early development of Drosophila melanogaster

The pattern of DNA polymerase activity in developing Drosophila melanogaster has been studied in seven stages of embryonic development as well as in unfertilized eggs. The crude polymerase-containing extracts, most likely of cytoplasmic origin, utilize, in the following order of decreasing template efficiency, "activated" calfthymus DNA, poly(A).oligo(dT), and poly(A).oligo(U). The highest enzymes levels occur in unfertilized eggs; the activity remains high during the first 9 hr of embryogenesis, but shows a progressive decline in the later stages. Deoxyribonuclease exhibits a similar trend. The unfertilized eggs of two genotypically different females had nearly identical levels of DNA polymerase.