One copy of Su(var)2091 strongly suppresses position effect variegation (PEV) at the w locus caused by In(1)wm4.
One copy of Su(var)2091 is unable to suppress the telomeric position effect (TPE) in stocks carrying a variegating P{hsp26-pt-T}39C-5 insertion at the telomere of the left arm of chromosome two.
Moderate to strong maternal effects as seen by elevated w+ eye pigment levels in non-suppressor bearing offspring of Su(var) females. Removal of segments of heterochromatin from the genome by loss of the Y chromosome abolishes the suppression of the position effect variegation phenotype. The effect of the Su(var)209 allele is unchanged in heterozygotes with Df(2R)M41A10 (which lacks 2R heterochromatin). Su(var)204 and Su(var)209 complemented all other mutants with respect to female fecundity.
Dominant suppressor of position effect variegation in eye pigment caused by In(1)wm4 or In(2R)bwVDe2. The suppressor effect on the variegation caused by In(1)wm4 is substantially reduced or eliminated entirely in male XO flies lacking a Y chromosome.