Distinguishing Among Evolutionary Models for the Maintenance of Gene Duplicates

• Published in: The Journal of heredity Vol. 100; no. 5; pp. 605 - 617
• Main Author: Hahn, Matthew W
• Format: Journal Article
• Language: English
• Published: United States The American Genetic Association 01.09.2009; Oxford University Press; Oxford Publishing Limited (England)
• Subjects: Adaptation; Animals; Caenorhabditis elegans - genetics; Crossing Over, Genetic; DDC; duplication; Evolution, Molecular; Evolutionary biology; Gene amplification; Gene Duplication; Genetics, Population; Models, Genetic; paralogs; Polyploidy; Population genetics; positive selection; Recombination, Genetic - genetics; Retroelements - physiology; Selection, Genetic
• ISSN: 0022-1503; 1465-7333
• DOI: 10.1093/jhered/esp047

Determining the evolutionary forces responsible for the maintenance of gene duplicates is key to understanding the processes leading to evolutionary adaptation and novelty. In his highly prescient book, Susumu Ohno recognized that duplicate genes are fixed and maintained within a population with 3 distinct outcomes: neofunctionalization, subfunctionalization, and conservation of function. Subsequent researchers have proposed a multitude of population genetic models that lead to these outcomes, each differing largely in the role played by adaptive natural selection. In this paper, I present a nonmathematical review of these models, their predictions, and the evidence collected in support of each of them. Though the various outcomes of gene duplication are often strictly associated with the presence or absence of adaptive natural selection, I argue that determining the outcome of duplication is orthogonal to determining whether natural selection has acted. Despite an ever-growing field of research into the fate of gene duplicates, there is not yet clear evidence for the preponderance of one outcome over the others, much less evidence for the importance of adaptive or nonadaptive forces in maintaining these duplicates.