Originally published as Genetics Published Articles Ahead of Print on December 28, 2006.

Genetics, Vol. 175, 1539-1542, March 2007, Copyright © 2007
doi:10.1534/genetics.106.066407

A Distinct Type of Heterochromatin Within Drosophila melanogaster Chromosome 4

Department of Biology, Washington University, St. Louis, Missouri 63130

2 Corresponding author: Department of Biology, 1 Brookings Dr., Campus Box 1229, Washington University, St. Louis, MO 63130.
E-mail: selgin{at}biology.wustl.edu

Studies of transcriptional gene silencing in Drosophila melanogaster suggest that most of chromosome 4 resembles pericentric heterochromatin. However, some modifiers of position-effect variegation, including chromosome 4 dosage and loss of SU(VAR)3-9, have different effects on silencing in pericentric vs. distal arm chromosome 4 heterochromatin, distinguishing these two heterochromatin types.