Essential Genetics 6th Edition by Daniel Hartl

Exercise 6

Which of the following statements is true?
(a) The odd-skipped mutation exemplifies a pair-rule gene. One would expect that a loss-of-function phenotype of an odd-skipped mutant would be deletion of alternating segments of the larva.
(b) Mutations in several different genes result in flies lacking wings, but when each of these genes is expressed alone, it does not lead to wing development. Thus, these genes are necessary but not sufficient for wing development.
(c) The phenotype of a particular Drosophila mutant is the development of a larva lacking all denticle belts but having the normal number of segments. This is a mutation in a gap gene.