The eyes of Drosophila develop from imaginal discs, groups of cells set aside in the fly embryo that differentiate into the adult structures during the pupal stage. Despite their importance in nature, eyes are dispensable for fruit-fly life in the laboratory. Devise a genetic screen to identify genes directing development of the fly eye.
Match the terms to the appropriate blanks to complete the sentences. Terms can be used once, more than once, or not at all.
Male flies_______ for dark body (db) are fed EMS to induce mutations and then mated to females___________ for a balancer chromosome 3 containing the db allele and the dominant marker CyO. Individual F_1 males that have ___________wings and__________ bodies are selected and mated back to a female from the chromosome 3 balancer strain to create many independent F_2 lines. F_2 progeny with__________ wings and ___________bodies will be__________ heterozygous for the new mutations. Interbreeding the F_2 will create many independent F_3 populations. The straight-winged flies within each population will be recessive for new mutations on chromosome 3, and the rest will be____________ for the mutation. F_3 that have _________winged flies with eye abnormalities identify fly lines with mutations on chromosome 3 affecting eye development.
1. Homozygous
2. Heterozygous
3. Curly
4. Straight
5. Dark
6. Light