By contrast, testes from Egfr-/+ flies had a significantly different distribution of phenotypes, with only a minority of testes (45%, n = 142) regaining CySCs and early cyst cells while maintaining a hub and germ cells; most testes had only a hub or a hub and germ cells at their apex (Figure 4D; Table 5). The gene discussed is EGFR; the disease is cyst.