DNA polymorphism in cytokine genes based on length variation in simple-sequence tandem repeats.

The possibility of the involvement of cytokines in the genetic predisposition to various diseases has been suggested by a large variety of studies. However, the study of potential disease linkage of cytokine genes has been hampered by a lack of sufficiently polymorphic markers at the restriction fragment length polymorphism (RFLP) level. We have investigated the distribution, the length polymorphism, the informativeness, and the efficiency of analysis, of simple-sequence tandem repeats in the mouse cytokine genes. Highly polymorphic sequences have been identified in the IL-1 beta, IL-1ra, IL-2, IL-4, IL-5, IL-6, IL-7, and IFN-gamma genes. The utility and the value of these sequences as gene markers is exemplified by mapping the IL-7 gene to mouse chromosome 3 close to pgk-1ps3 and Car-2 loci and the IFN-gamma gene to chromosome 10 near the pg locus. Advantages of short tandemly repeated sequences as genetic markers are discussed in comparison with RFLPs.