Figure 4.—

Immunolabeling of R. raphanurus squashed spermatocytes with anti-SCP3 (green) and MPM-2 (red). Single focal planes are shown. SCP3 labels both autosomal LEs (arrows) and sex chromosomal AEs (X, Y). However, MPM-2 antibody appears only on the AEs of sex chromosomes and on the dense plate. (A and B) Early pachytene. Sex chromosomes occupy different domains in the nucleus. (A′ and B′) Detail of the sex chromosomes. Note that the labeling of both antibodies is almost identical. (C–D′) Midpachytene. Sex chromosomes have approached and start to contact by the ends of their AEs. (E–F′). Late pachytene. Sex chromosomes are paired and the DP has formed. Bars: 5 μm for A–F; 1 μm for A′–F′.