Sperm nuclear basic proteins and sperm chromatin organization in fish

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