Orthologs, Paralogs, and Evolutionary Genomics

Annual Review of Genetics

Vol. 39:309-338 (Volume publication date 15 December 2005)
First published online as a Review in Advance on August 30, 2005
https://doi.org/10.1146/annurev.genet.39.073003.114725

Abstract

AbstractOrthologs and paralogs are two fundamentally different types of homologous genes that evolved, respectively, by vertical descent from a single ancestral gene and by duplication. Orthology and paralogy are key concepts of evolutionary genomics. A clear distinction between orthologs and paralogs is critical for the construction of a robust evolutionary classification of genes and reliable functional annotation of newly sequenced genomes. Genome comparisons show that orthologous relationships with genes from taxonomically distant species can be established for the majority of the genes from each sequenced genome. This review examines in depth the definitions and subtypes of orthologs and paralogs, outlines the principal methodological approaches employed for identification of orthology and paralogy, and considers evolutionary and functional implications of these concepts.

Footnotes:

1The U.S. Government has the right to retain a nonexclusive, royalty-free license in and to any copyright covering this paper.

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