Domain Duplication and Gene Elongation


A protein domain is a well‐defined region within a protein that performs a specific function. Thus duplication of a protein domain may enhance the function of the protein. The fact that many extant proteins contain duplicated domains suggests that present‐day complex proteins have evolved from simple proteins mainly via domain duplication.

Keywords: protein domain; duplication; exons; module; new function

Figure 1.

Protein kinase domain. Key structural elements are indicated. (Reproduced from Huse and Kuriyan p. 276 .)

Figure 2.

Possible relationships between the arrangement of exons in a gene and the structural domains of the protein it encodes: (a) each exon corresponds exactly to a structural domain; (b) the correspondence is only approximate; (c) an exon encodes two or more domains (d) a single structural domain is encoded by two or more exons and (e) lack of correspondence between exons and domains. The four structural domains of the protein are designated by different types of shading. (Reproduced from Li and Graur .)



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Li, Wen‐Hsiung, and Makova, Kateryna D(Jul 2006) Domain Duplication and Gene Elongation. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1038/npg.els.0005097]