Drosophila Mutations Such as Bcd, If Homozygous in the Mother

Multiple Choice

Drosophila mutations such as bcd, if homozygous in the mother, produce offspring with lethal defects, no matter what the genotype of the offspring. For some other genes, the mutant phenotype can be "rescued" by introducing a wild- type allele into the embryo. What is the reason for these different outcomes?

A) Non- rescuable mutations are of paternal origin.
B) bcd is a Hox gene.
C) Rescuable mutations act as dominants.
D) Rescue requires recombination between the maternal and introduced alleles.
E) bcd is a maternal effect mutation.