Sperm nuclear basic proteins (SNBPs) have been shown to consist of three main types: histone (H type), protamine-like (PL type) and protamine (P type). Fishes represent a unique group of vertebrates in that it includes species that contain representative proteins of each type. Phylogenetically, the different SNBP types exhibit a sporadic distribution that is not random and is the result of vertical evolution. Each of the SNBP types bind to DNA in a distinctive way providing the nuclei with a highly compacted chromatin organization that is characteristic of the sperm head. An improved understanding of the packing of chromatin has implications for aquaculture. The diverse nature of the SNBPs involved in fish sperm provides an excellent tool for further understanding chromatin epigenetics.

Peer Reviewed