Mutants show an enhancement of the position effect variegation seen in In(1)wm4. This phenotype shows a cooperative effect with the suppression of PEV seen in XXY females, resulting in a variegated eye phenotype.
Su(var)205+tSa is a non-enhancer of suppressor of variegation phenotype of Su(var)3-96
The combination of Su(var)3-96 and either Su(var)3-7+t10.4 or Su(var)205+tSa leads to a Su(var)3-96 like position effect variegation (PEV) phenotype - i.e. suppression of PEV in In(1)wm4. The suppressor effect of an extra X chromosome is epistatic to the enhancer effect of Su(var)205+tSa mutants.