Figure 1.

Screen for hybrid-dysgenesis-induced X-linked lethals in an e(r)^p2-containing X chromosome. In this scheme, the only mobile P element is the one in e(r)^p2. This element is mobilized by the introduction of the active but immobilized P element, Δ2–3. Tr[e(r)⁺]^SS is a construct carrying e(r)⁺ and w⁺.¹ In cross 3, males were individually mated to 5 C(1)DX, y f females, since each male represents a single mutagenized X chromosome. Crosses which produced red-eye males, but no white-eye males were kept as possible X-linked lethal stocks. From 10,024 stocks, one lethal stock was isolated.