Distribution of distances between centers of active replication in chromatin fibers. We measured between the centers of adjacent EdU tracks that overlapped with GINS proteins (n = 116) to determine the average distance between sites of active replication. A total of 24 fibers were used for this analysis ranging in size from approximately 1.1 to 7.4 Mb. The frequency distribution is shown in this chart. Numbers on the X-axis represent the upper limit of each bin. We found that the average distance was 667 kb with standard error of the mean of 66. Minimum size = 35 kb, maximum size = 3,505 kb, median 390 kb.