The CD8 alpha locus is located on the telomere side of the immunoglobulin kappa locus at a distance of 2 Mb.

The immunoglobulin kappa and CD8 alpha loci had been mapped by in situ hybridization to the short arm of chromosome 2 at 2cen-p11.2 and 2p1, respectively, but probes derived from the two loci did not hybridize to the same large PFGE fragments. We have now succeeded in linking the two loci on a 3.0-Mb fragment from a partial NruI digest. A new hybridization probe located between the two loci provided additional linking fragments and allowed the distance to be determined as 2.0-2.2 Mb.