Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If You Use a Screen Reader

This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.

Multiple Fitness Peaks and Epistasis

Michael C. Whitlock, Patrick C. Phillips, Francisco B.-G. Moore and Stephen J. Tonsor
Annual Review of Ecology and Systematics
Vol. 26 (1995), pp. 601-629
Published by: Annual Reviews
Stable URL: http://www.jstor.org/stable/2097221
Page Count: 29
  • Read Online (Free)
  • Download ($36.00)
  • Subscribe ($19.50)
  • Cite this Item
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Multiple Fitness Peaks and Epistasis
Preview not available

Abstract

The importance of genetic interactions in the evolutionary process has been debated for more than half a century. Genetic interactions such as underdominance and epistasis (the interaction among genetic loci in their effects on phenotypes or fitness) can play a special role in the evolutionary process because they can create multiple fitness optima (adaptive peaks) separated by fitness minima (adaptive valleys). The valleys prevent deterministic evolution from one peak to another. We review the evidence that genetic interaction is a common phenomenon in natural populations. Some studies give strong circumstantial evidence for multiple fitness peaks, although the mapping of epistatic interactions onto fitness surfaces remains incompletely explored, and absolute proof that multiple peaks exist can be shown to be empirically impossible. We show that there are many reasons that epistatic polymorphism is very difficult to find, even when interactions are an extremely important part of the genetic system. When polymorphism results in the presence of multiple fitness peaks within a group of interbreeding populations, one fitness peak will quickly be nearly fixed within all interbreeding populations, but when epistatic or underdominant loci are nearly fixed, there will be no direct evidence of genetic interaction. Thus when complex landscapes are evolutionarily most important, evidence for alternative high fitness genetic combinations will be most ephemeral. Genetic interactions have been most clearly demonstrated in wide crosses within species and among closely related species. This evidence suggests that genetic interactions may play an important role in taxonomic diversification and species-level constraints. Population genetic analyses linked with new approaches in metabolic and molecular genetic research are likely to provide exciting new insights into the role of gene interactions in the evolutionary process.

Page Thumbnails

  • Thumbnail: Page 
601
    601
  • Thumbnail: Page 
602
    602
  • Thumbnail: Page 
603
    603
  • Thumbnail: Page 
604
    604
  • Thumbnail: Page 
605
    605
  • Thumbnail: Page 
606
    606
  • Thumbnail: Page 
607
    607
  • Thumbnail: Page 
608
    608
  • Thumbnail: Page 
609
    609
  • Thumbnail: Page 
610
    610
  • Thumbnail: Page 
611
    611
  • Thumbnail: Page 
612
    612
  • Thumbnail: Page 
613
    613
  • Thumbnail: Page 
614
    614
  • Thumbnail: Page 
615
    615
  • Thumbnail: Page 
616
    616
  • Thumbnail: Page 
617
    617
  • Thumbnail: Page 
618
    618
  • Thumbnail: Page 
619
    619
  • Thumbnail: Page 
620
    620
  • Thumbnail: Page 
621
    621
  • Thumbnail: Page 
622
    622
  • Thumbnail: Page 
623
    623
  • Thumbnail: Page 
624
    624
  • Thumbnail: Page 
625
    625
  • Thumbnail: Page 
626
    626
  • Thumbnail: Page 
627
    627
  • Thumbnail: Page 
628
    628
  • Thumbnail: Page 
629
    629