Evolution Acts on Enhancer Organization to Fine-Tune Gradient Threshold Readouts
Figure 3
Analysis of NEE Activities in Transgenic D. melanogaster Embryos
(A–D) NEE-driven lacZ transgenes assayed in D. melanogaster embryos from the brk (A), vn (B), rho (C), and vnd (D) loci demonstrate that D. virilis enhancers tend to drive broader stripes than D. melanogaster enhancers. Similarly, D. melanogaster enhancers tend to drive broader stripes than D. pseudoobscura enhancers.
(E) Quantification of the widths of lateral stripes of expression at 50% egg length across multiple embryos from several lines supports this general trend.
The in situ staining experiments in this figure were conducted in parallel and with the same anti-sense lacZ probe to facilitate comparisons.