c-Myb has long been known as a factor of many leukemias and lymphomas in mammals and birds. Vertebrates possess 3 forms of the Myb gene, A-Myb, B-Myb, and c-Myb, whereas Drosophila melanogaster, however, only possess one copy of the Myb gene, Dm-Myb, which results in fatality before reaching adulthood (Manak, Mikitu, Lipsick, 2002). Myb has also been shown to be required for the proper activation of G2/M cell cycle genes (Georlette et al., 2007). The results of several other experiments lead our lab to suspect that Myb is involved in facultative heterochromatin stabilization. Chromatin, made up of DNA and associated proteins, can be euchromatic or heterochromatic; euchromatin is mainly associated with active transcription, whereas heterochromatin is associated with repressed transcription. Active euchromatin and repressive heterochromatin are established by post-translational marks such as methyl groups placed on the histone around which DNA is wrapped. Histone 3 lysine 4 is methylated to promote active transcription, whereas histone 3 lysine 27 is methylated to promote the formation of facultative heterochromatin (which is associated with…