Sandler and Mange (1973) suppose E(da) to be a consequence of the break in 2R.
Effect enhanced by reduced heterochromatic content of progeny.
One dose of E(da)1 in da1/+ females, in either coupling or repulsion with da1, reduces the number of daughters among their progeny; without effect in da1/+ males. da1, E(da)1/SM1 females are daughterless.
E(da)1 is an enhancer of phenotype of da1
Maternal effect of E(da)1 strong at 29oC but absent at 17oC. Sxlf1/+;da1 E(da)1/+ females produce no Sxlf1/+ daughters at 29oC.
E(da)1/abo1 females produce normal sex ratios; show zygotic suppression of the maternal effect of homozygous abo1.