The cleavage of Drosophila melanogaster DNA by restriction endonucleases

Abstract

Drosophila melanogaster DNA, together with λ and E. coli DNAs as controls, was digested with three different restriction endonucleases: EcoRI, Hind, and Hae. The size distributions of the segments were characterized by gel electrophoresis. More than 85% of the D. melanogaster DNA was found in a broad distribution of segment lengths consistent with random location of restriction sites. However, some DNA was spared and recovered in very long (≥20500bp) segments. These segments proved to be mostly simple sequence DNA. No complex spared segments could be found in Hind and Hae digests, while 50% of the spared EcoRI segments had a complexity exceeding that of the E. coli DNA spared by this enzyme. These data do not support the hypothesis that chromomeres contain long regions of purely tandemly repeating sequences.