Internal deletion of sequences encoding amino acid residues V288-E473.

dec-1^{fc106ΔV288-E473} is a dominant female sterile mutation that can be used as an eggshell marker for complete follicle cell clones of a mutation of interest; FRT-mediated recombination in females transheterozygous for a mutation of interest and dec-1^{fc106ΔV288-E473} can generate egg chambers containing homozygous mutant follicle cells that lack dec-1^{fc106ΔV288-E473}. Eggs derived from egg chambers with large or complete mutant follicle cell clones are readily identifiable because they remain intact, whereas those produced by non-mutant follicular epithelia retaining dec-1^{fc106ΔV288-E473} collapse.