Substrain of BDIV, from cross between BDI and BDII single mating pair, with selection for coat color alleles (Druckrey 1971). BDIV/IFZ rats have been inbred in the Institute of Cell Biology, Essen and later in the Central Animal Facility for about 45 years. BDIX/Ifz rats are extremely resistant to ENU-induced development of tumors of the peripheral nervous System.