Fig. 3

The most important histone post-translational modifications at particular stages of human spermatogenesis. a The main histone post-translational modifications during embryonal development, mitotic proliferation, and spermiogenesis, together with indication of the cell type, their ploidy and morphology. b The main histone post-translational modifications during prophase I (the most important stage of first meiotic division in primary spermatocytes). Epigenetic modifications found on autosomal chromosomes are marked in black, while modifications representative for sex chromosomes are marked in blue. PGCs – primordial germ cells, SSCs – spermatogonial stem cells, SPC – spermatocyte, SPD – spermatid, ac – acetylation, me – methylation, ph – phosphorylation, ub – ubiquitination, 1n – haploid genome, 2n – diploid genome, 4n – tetraploid genome