Pachytene phenotypes of PWK F1 males.

Age, male age (weeks); N, number of counted pachynemas from a total of two or three males; SB, AB, 0B, % pachytene spermatocytes carrying a normal sex body and all chromosomes synapsed (SB), an abnormal sex body (AB, a sex body containing unsynapsed autosomes), and neither abnormal nor sex body (0B; always carried also unsynapsed chromosomes). See Figure 2A for representative phenotypes and Table 1 for other abbreviations. Antibodies against SYCP3, SYCP1, and γH2AX were used to stage the cells on chromosomal spreads. See the text for statistical evaluations.