Document Detail

Compensatory evolution and the origins of innovations.
MedLine Citation:
PMID:  23335336     Owner:  NLM     Status:  MEDLINE    
Cryptic genetic sequences have attenuated effects on phenotypes. In the classic view, relaxed selection allows cryptic genetic diversity to build up across individuals in a population, providing alleles that may later contribute to adaptation when co-opted--e.g., following a mutation increasing expression from a low, attenuated baseline. This view is described, for example, by the metaphor of the spread of a population across a neutral network in genotype space. As an alternative view, consider the fact that most phenotypic traits are affected by multiple sequences, including cryptic ones. Even in a strictly clonal population, the co-option of cryptic sequences at different loci may have different phenotypic effects and offer the population multiple adaptive possibilities. Here, we model the evolution of quantitative phenotypic characters encoded by cryptic sequences and compare the relative contributions of genetic diversity and of variation across sites to the phenotypic potential of a population. We show that most of the phenotypic variation accessible through co-option would exist even in populations with no polymorphism. This is made possible by a history of compensatory evolution, whereby the phenotypic effect of a cryptic mutation at one site was balanced by mutations elsewhere in the genome, leading to a diversity of cryptic effect sizes across sites rather than across individuals. Cryptic sequences might accelerate adaptation and facilitate large phenotypic changes even in the absence of genetic diversity, as traditionally defined in terms of alternative alleles.
Etienne Rajon; Joanna Masel
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2013-01-18
Journal Detail:
Title:  Genetics     Volume:  193     ISSN:  1943-2631     ISO Abbreviation:  Genetics     Publication Date:  2013 Apr 
Date Detail:
Created Date:  2013-04-02     Completed Date:  2013-11-27     Revised Date:  2014-04-01    
Medline Journal Info:
Nlm Unique ID:  0374636     Medline TA:  Genetics     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1209-20     Citation Subset:  IM    
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MeSH Terms
Adaptation, Biological / genetics
Evolution, Molecular*
Models, Genetic*
Polymorphism, Genetic
Population / genetics

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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