Meiotic progression and chromosome paring in XX, XO and XY oocytes.

(A) Meiotic progression in XX, XO and XY oocytes. The graphs show the percentages of the meiotic stage at the day of culture indicated. L, leptotene; Z, zygotene; P, pachytene; D, diplotene. (B) Pairing of homologous chromosomes in XX, XO and XY oocytes. Images show the immunofluorescence analysis of SYCP3 (white) and SYCP1 (red), and FISH analysis of the X chromosome (green) and Y chromosome (purple). The dashed squares in the merged images are shown at high magnification (right). The numbers of samples showing the phenotype are shown with the total number tested (left). Arrowheads indicate asynapsed bivalents at the end of the chromosomes. Scale bars, 10 μm. (C) Pairing rates of autosomes and sex chromosomes. Each value was calculated from three independent experiments (see also Materials and Methods). P values were calculated by Tukey’s HSD test. ***P<0.001, **P<0.01, *P<0.05; NS, not significant.