The study of nuclear molecular architecture during gametogenesis represents one approach towards the deciphering of the molecular organization of eukaryotic chromatin. During spermatogenesis, chromatin undergoes several dynamic transitions, which are often associated with important changes not only in its physical conformation but even in its composition and structure. Dynamic alterations in chromatin structure mediated by postsynthetic histone modification and DNA methylation constitute a major regulatory mechanism of gene function of eukaryotes. Using transmission electron microscopy and molecular investigations, some peculiar aspects of chromatin organization and evolution in spermatogenesis of the crested newt Triturus cristatus were investigated. We focused our investigations on the dynamics of chromatin structure after treatment with TSA (a histone deacetylase inhibitor).