l(2)57Ac << bk1 << l(2)57Ad << exu << bk2

Homozygotes exhibit mild head defects that include disruptions of the pattern of ventral pharyngeal ribs.

Selected on basis of loss of P{w⁺,ry⁺} at 57B1--57B2 of Df(2R)exu1.

The Df(2R)exu2 chromosome acts as a dominant moderate suppressor of telomeric silencing (assayed using the effect of the chromosome on the eye colour phenotype of flies carrying "P{w^var}KR3-2", a stable "brown-red" variant of the P{3'WP-2,w^var}2Lt insertion), but this is a false positive result (the suppressor is not within the bounds of the deficient region) because the suppressor maps to the tip of 2L rather than to the site of the deficiency.