Vertebrate Immune System: Evolution

Abstract

The vertebrates possess unique adaptations for immune defense that have apparently evolved gradually over the long evolutionary history of the vertebrate lineage. Molecular diversity is one of the hallmarks of vertebrate immune mechanisms, and molecular analyses have clearly implicated natural selection as the major factor in promoting molecular diversity and a consequent enhanced immune surveillance.

Keywords: immune system; immunoglobulin; innate immunity; major histocompatibility complex; NF‐κB

Figure 1.

Schematic phylogeny of the chordates, indicating the time of origin of molecules involved in specific immunity in vertebrates. Ig: immunoglobulin; MHC: major histocompatibility complex; Myr: million years; TCR: T‐cell receptors.

Figure 2.

Phylogeny of the Toll family of receptors from insects and vertebrates TLR: Toll‐like receptor; dG=amino acid distance (corrected for multiple hits on the assumption that rates vary among sites following of gamma distribution). (Reproduced with permission from Friedman and Hughes, .)

Figure 3.

Mean numbers of synonymous (dS) and nonsynonymous (dN) nucleotide substitutions per site in comparisons between orthologous human and rodent immunoglobulin superfamily C2‐set domains. N: number of genes compared. (Adapted with permission from Hughes, .)

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References

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Further Reading

Cooper MD and Alder MN (2006) The evolution of adaptive immune systems. Cell 124: 815–822.

Du Pasquier L (2004) Speculations on the origin of the vertebrate immune system. Immunology Letters 92: 3–9.

Flajnik MF and Du Pasquier L (2004) Evolution of innate and adaptive immunity: can we draw a line? Trends in Immunology 25: 640–644.

Hughes AL (1998) Protein phylogenies provide evidence of a radical discontinuity between arthropod and vertebrate immune systems. Immunogenetics 47: 283–296.

Hughes AL (1999) Adaptive Evolution of Genes and Genomes. New York: Oxford University Press.

Hughes AL (2002) Natural selection and the diversification of vertebrate immune effectors. Immunological Reviews 190: 161–168.

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Web Links

recombination activating gene 1 (RAG1); LocusID: 5896. LocusLink: http://www.ncbi.nlm.nih.gov/LocusLink/LocRpt.cgi?l=5896

recombination activating gene 2 (RAG2); LocusID: 5897. LocusLink: http://www.ncbi.nlm.nih.gov/LocusLink/LocRpt.cgi?l=5897

recombination activating gene 1 (RAG1); MIM number: 179615. OMIM: http://www.ncbi.nlm.nih.gov/htbin‐post/Omim/dispmim?179615

recombination activating gene 2 (RAG2); MIM number: 179616. OMIM: http://www.ncbi.nlm.nih.gov/htbin‐post/Omim/dispmim?179616

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How to Cite close
Hughes, Austin L(Apr 2008) Vertebrate Immune System: Evolution. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0006125.pub2]