RECOMBINATION, MUTATION, OR CONSTITUTIVE EXPRESSION AT A GM LOCUS AND FAMILIAL-HYPERGAMMAGLOBULINEMIA

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  • 1 January 1977
    • journal article
    • research article
    • Vol. 29  (5) , 523-536
Abstract
In a hypercholesterolemic Lebanese family, an uncommon Gm haplotype carrying an unexpected C.gamma.1 gene was inherited by only 1 of 10 siblings. A new recombination during the maternal or paternal meiosis could explain its formation. According to this hypothesis, the data would be informative for the linkage relationship between the .gamma.-cistrons and the .alpha.2-cistron. The latter might be located near the N-terminal side of the .gamma.-cistron linkage group, and the sequence of genes would be .alpha.2, .gamma.4, .gamma.2, .gamma.3, and .gamma.1. A mutation could also effect the change from Glm (codons AAA and AAG) to Glm (codons AGA and AGG). Another alternative is to postulate a constitutive expression of a C.gamma.1 structural gene which, normally, would not be expressed. The uncommon derepression could be the consequence of uncommon cellular response to environmental, pathological or metabolic perturbation of a regulatory mechanism.