Figure 1.

Stimulation of the mini-white gene in transgenic lines. Levels of eye pigmentation in transgenic lines in which the deletion of the white promoter (A) resulted in the white color of the eyes, (B) had no effect on eye pigmentation, or (C) partially reduced it. The white gene is shown as a white rectangle with the arrow indicating the direction of transcription; the white square marked ‘Prw’ represents the white promoter. The black box shows the promoter deletion in mini-white. Downward arrows indicate cleavage sites for Cre recombinase; in construct names, the corresponding excisable element is parenthesized. The ‘white’ columns show the numbers of transgenic lines with the white eye pigmentation levels. N is the number of lines in which flies acquired a new w phenotype relative to the initial lines. T is the total number of lines examined for each particular construct.