A Possible Case of Position Effect on DNA Replication in DROSOPHILA MELANOGASTER

The behavior of T(3;4)10 provides evidence that the centromere of 4 is not in the doublet 101D3,4, and that most of what has been called the left arm of 4 should be called basal 4R. Basal 4R usually does not replicate as much as the tip of 4R when 4 is in its normal position in the chromocenter. Translocated to the tip of 3R, however, basal 4R attains a width equal to that of the rest of the arm-a possible position effect on DNA replication.