Reduced number of COs in HFM1-deficient spermatocytes.

<p>(a) Spread nuclei of wild-type and <i>Hfm1^−/−</i> pachytene spermatocytes immunostained for SYCP3 and MLH1. Magnification bar represents 5 µm. (b) Quantification of autosomal MLH1 foci per pachytene cells. See <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1003383#pgen-1003383-t001" target="_blank">Table 1</a> for summary of means, standard deviations, and results of statistical tests. (c) Metaphase spreads of wild-type and <i>Hfm1^−/−</i> spermatocytes. Note the reduced number of bivalents (arrowheads) and increased number of univalents (tailed arrows) in <i>Hfm1^−/−</i> cells. X and Y indicate the sex chromosomes. (d) Quantification (mean ± standard deviation) of metaphase bivalents per cell. (e) Representative diplotene wild-type and <i>Hfm1^−/−</i> spermatocytes stained with anti-SYCP3 and CREST (a centromere marker) antibody. Note the increase in univalent chromosomes of knockout cells (arrowheads). Tailed arrows indicate examples of forming chiasmata in wild-type spermatocytes. Magnification bar represents 5 µm. (f) Quantification of cells in (e).