A POSSIBLE CASE OF POSITION EFFECT ON DNA REPLICATION IN DROSOPHILA MELANOGASTER

Paul A. Roberts ¹

¹ Department of Zoology, Oregon State University, Corvallis Oregon 97331

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.