Distributions of the distances between c-MYC and unique telomere 14q sequences (TM_m ; lying adjacent to the Ig heavy chain locus) in human lymphocytes incubated for 50 hours with PHA (A) and in human fibroblasts (B). The curves represent the theoretical distributions calculated by Monte-Carlo simulation using experimentally determined center-to-gene distributions (not shown). Human fibroblasts (VF-10) were grown in RPMI medium supplemented with 10% fetal calf serum, 0.5% L-glutamine, 1% glucose, and antibiotics at 37°C to the confluent state.