Atypical histone H2B. Nucleosomes containing it are structurally and dynamically indistinguishable from those containing conventional H2B. However, unlike conventional H2B, does not recruit chromosome condensation factors and does not participate in the assembly of mitotic chromosomes. May be important for telomere function. The nucleosome is a histone octamer containing two molecules each of H2A, H2B, H3 and H4 assembled in one H3-H4 heterotetramer and two H2A-H2B heterodimers. The octamer wraps approximately 147 bp of DNA. Testis-specific. Present in sperm cells (at protein level). In contrast to other H2B histones, it does not contain the conserved residue in C-terminus that is the target of monoubiquitination. Ortholog in primates, but not in rodents. Belongs to the histone H2B family.