Replicating DNA molecules from fertilized eggs of Cochliomyia hominivorax (Diptera)

DNA samples were prepared from the early embryos of the screwworm, Cochliomyia hominivorax. When they were examined under the electron microscope, linear DNA molecules containing one or more replicating loops arrayed tandemly were abundantly observed. The average size of replicating loops is 0.83 μ. Further, the average distance between center-to-center of adjacent loops was found to be 2.3 μ. Both these numbers are considerably smaller than those of D. melanogaster. Comparisons between the developmental time and the replication pattern of these two insects are discussed.