Map position of Igh-Oxa gene within the Igh region of the DBA/2 mouse strain.

Mice of 23 BXD recombinant inbred strains derived from the cross of C57BL/6J and DBA/2J were typed for the presence of a public idiotype found in the antibodies against the hapten phenyloxazolone (phOx) produced by DBA/2 mice. The marker is under the control of an immunoglobulin heavy-chain variable region gene, Igh-Ox. Eleven out of the 23 BXK strains shared the public idiotype with the DBA/2 progenitor, while 12 other BXD strains were negative, like the C57BL/6 progenitor. The Igh-Ox marker was inherited concordantly with allotype in all BXD strains except BXD-27, which carries the Igh-1c allotype of DBA/2 but lacks the Igh-Ox idiotype. The Igh-Ox marker was inherited concordantly with 4 other Igh-V markers (Igh-Np, Igh-Nb, Igh-Bgl, and Igh-Gte) in all BXD strains except BXD-20, which has the DBA/2 alleles at Igh-1 and Igh-Ox but resembles C57BL/6 at the other 4 markers. On the basis of these results the Igh-Ox marker is tentatively placed between Igh-C and the rest of the Igh-V markers.