Probable chimeric globin with a bis-histidyl six-coordinate heme-iron atom through which it could bind dioxygen, carbon monoxide and nitric oxide (PubMed:22115833). Required for sperm flagellum formation and maturation of elongating spermatids, thus playing an essential role in male fertility (PubMed:36995441). . This is the function of ADGB (androglobin, Ensembl gene identifier ENSG00000118492).