T-cell receptor genes (TCR) of man

In the germ line, the genes for the ! chain of the
T-cell receptor consist of 75–100 variable segments
(V!), two D segments (D!1, D!2), two
joining segments (J!1, J!2), and two constant
segments (C!1, C!2). The genomic organization
of the genes for the ", #, and $ chains is similar.
During T-lymphocytematuration, different segments
are joined together by somatic recombination
as during B-cell maturation. In a given T
cell, only one of the two "-chain loci and only
one of the two !-chain loci become functionally
rearranged and expressed (allelic exclusion). As
in the rearrangement of immunoglobulin
genes, different mechanisms help produce diversity
of the T-cell receptor genes. The
genomic organization in humans and mice is
very similar. The !-chain genes are located on
chromosome 7 in humans and on chromosome
6 in mice. The "- and #-chain gene loci are located
on chromosome 14 in both humans and
mice. The $-chain genes lie on chromosome 7 in
humans and on chromosome 13 in mice.