Segregation of polymorphic T-cell receptor genes in human families.

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Abstract
Polymorphism in the genes encoding the constant (C) region of the .beta. chain of the T-cell antigen receptor (CT.beta., also called C.beta.) was detected by molecular genotyping analyses. In initial screenings, a panel of restriction endonucleases was used to digest DNA samples from 2 individuals; the digested samples were subjected to Southern blot analyses using a CT.beta. probe. The enzyme BglII revealed restriction-fragment-length polymorphism in these samples and was subsequently used to test 59 individual members of 8 different families. Polymorphic fragments detected in 6 of the families could be used to follow the segregation of T-cell receptor genes; in many cases maternal and/or paternal haplotypes could be assigned. All members of 2 additional families displayed a single CT.beta. hybridizing fragment. In 1 family the DNA sample from 1 of the children lacked an expected BglII restriction fragment. On the basis of analyses with other restriction enzymes, the most likely explanation is that the lymphoblastoid B-cell line used as a source of genomic DNA for this individual had rearranged or altered CT.beta. genes. Restriction-fragment-length polymorphisms used to discriminate CT.beta. haplotypes in families provide useful markers that will facilitate linkage studies and genetic analyses of T-cell function.