One copy of Su(var)2-1²¹⁵ strongly suppresses position effect variegation (PEV) at the w locus caused by In(1)w^m4.

One copy of Su(var)2-1²¹⁵ 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.

Heterozygotes show no effect on crossing over between kni and p^p.

Homozygous embryos are semi-viable. 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)2-1²¹⁵ allele is reduced in heterozygotes with Df(2R)M41A10 (which lacks 2R heterochromatin). Viability of the Su(var)2-1²¹⁵ heterozygotes is butyrate-sensitive. The extent of hemizygous lethality is dramatically enhanced in the presence of extra heterochromatin (attachedXX/Y females) whereas the lethality did not occur in the absence of the Y (X/O males).

Dominant suppressor of position effect variegation in eye pigment caused by In(1)w^m4 or In(2R)bw^VDe2. Dominant suppressor of position effect variegation at the Sb locus caused by T(2;3)Sb^V. The suppressor effect on the variegation caused by In(1)w^m4 is substantially reduced or eliminated entirely in male XO flies lacking a Y chromosome.

homozygous lethal