Kalmar "achromatin" yawanci tana nufin ɓangaren tsakiya na tantanin halitta wanda ba shi da tabo ko launi a bayyane idan an duba shi a ƙarƙashin na'ura mai kwakwalwa. Musamman, yana nufin DNA a cikin wannan yanki wanda ke cikin yanayi mai tsawo ko mara ƙarfi, sabili da haka ba a iya gani tare da daidaitattun dabarun lalata. Ana bambanta Achromatin sau da yawa da "chromatin," wanda ke nufin ganuwa, dunƙulewar DNA da rukunin furotin waɗanda ke yin chromosomes yayin rarraba tantanin halitta.