Figure 4.18. The organization of the immunoglobulin heavy-chain C-region genes in mice and humans (not to scale).

Figure 4.18The organization of the immunoglobulin heavy-chain C-region genes in mice and humans (not to scale)

In humans, the cluster shows evidence of evolutionary duplication of a unit consisting of two γ genes, an ε gene and an α gene. One of the ε genes has become inactivated and is now a pseudogene (ψ); hence only one subtype of IgE is expressed. For simplicity, other pseudogenes are not illustrated, and the exon details within each C gene are not shown. The classes of immunoglobulins found in mice are called IgM, IgD, IgG1, IgG2a, IgG2b, IgG3, IgA, and IgE.

From: Structural variation in immunoglobulin constant regions

Cover of Immunobiology
Immunobiology: The Immune System in Health and Disease. 5th edition.
Janeway CA Jr, Travers P, Walport M, et al.
New York: Garland Science; 2001.
Copyright © 2001, Garland Science.

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