This multigenic deletion, present in C57BL/6NJ and C57BL/6NTac but not C57BL/6J inbred strains, is approximately 1 Mb in size and spans from Chr13:65.66Mb-66.67Mb which includes several lincRNA and pseudogenes along with Zfp998 and Zfp997, with the distal breakpoint falling between Zfp997 and Zfp640. (J:282526)