A maternal effect gene in Drosophila, called torso, is found as a recessive allele (t) that prevents correct development of the anterior- and posterior-most body structures. A wild-type male is crossed to a female of unknown genotype. This mating produces 100% larva that are missing their anterior- and posterior-most structures and therefore die during early development. What are the mother’s genotype and phenotype, and the grandmother’s genotype?
1. Mother: tt, normal; Grandmother: Tt or tt
2. Mother: tt, normal; Grandmother: Tt
3. Mother: Tt, normal; Grandmother: Tt
4. Mother: tt, mutant; Grandmother: Tt
5. Mother: Tt, mutant; Grandmother: Tt or tt