Figure 1

Meiotic product behavior in control and YA-deficient unfertilized eggs. In situ hybridization to the X and Y chromosomes in 0–15 minute old unfertilized eggs laid by X^X/Y, Ya⁺ (control) females (A-C) and X^X Ya²/Y (Ya² mutant) females (E-I). The X chromosome probe's signal is green, and the Y chromosome's is red. The green hybridization signal to the X chromosome also recognizes the maternal Y, Ya⁺ in control eggs (thus the Y, Ya⁺ is red and green in A-C). The X probe does not recognize the maternal Y chromosome in YA-deficient eggs (thus the Y is only red in E-I). (A-C) Unfertilized eggs containing (A) four separate haploid meiotic products, (B) one triploid nucleus with two X^X chromosomes and one Y chromosome, the result of association of three meiotic products, and one haploid Y-containing nucleus. (C) all four meiotic products associated. (D) Chart of percentages of nuclear distributions observed in the 22 control eggs. (E-I) YA-deficient unfertilized eggs containing (E) four haploid meiotic products, (F) one triploid nucleus with two X^X chromosomes and one Y chromosome, reflecting three associated meiotic products, and a separate haploid Y chromosome-containing nucleus, (G) two diploid nuclei, one containing two X^X chromosomes and the other containing two Y chromosomes. H and I both contain three DAPI-stained nuclei: (H) one Y-containing haploid nucleus, one diploid nucleus containing one X^X and one Y chromosome and one haploid X^X-containing nucleus, (I) two haploid X^X chromosome-containing nuclei and one diploid nucleus containing two Y chromosomes. (J) Chart of percentages of nuclear distributions observed in the 38 Ya² eggs. DAPI staining clearly showed the number of distinct nuclei per egg (four in A, E, two in B, F, G, one in C, three in H, I). Inset illustrations in each panel show the orientation of the egg and positions of DAPI stained nuclei inside (not drawn to scale). Bar = 4 μm for all panels.