Human genes for the immunoglobulin gamma-chain (Gm) allotypes and for the T cell receptor alpha-chain are distantly linked or unlinked

Abstract

Since the genes for two of the T cell receptor (TCR) chains (α and δ) and for the immunoglobulin (Ig) heavy chains (α, γ, δ, ε and μ) are all on the long arm of human chromosome 14, it is of interest to determine if they are genetically linked and, if so, how strongly. We tested genetic polymorphisms of the TCR α-locus and Ig γ-locus in 19 families comprising 107 memebers, and assessed the frequency of recombination between the two loci. The results rule out strong linkage: all recombination fractions below 0.26 gave lod scores less than -2 (odds less than: 1:100). Combining the data on maternal and paternal meisoses, the most likely recombination fraction was 0.5 (nonlinkage).