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Balancing Selection in Human Evolution

  1. Eric J Vallender,
  2. Welkin E Johnson

Published Online: 30 APR 2008

DOI: 10.1002/9780470015902.a0020759



How to Cite

Vallender, E. J. and Johnson, W. E. 2008. Balancing Selection in Human Evolution. eLS. .

Author Information

  1. New England Primate Research Center – Harvard Medical School, Southborough, Massachusetts, USA

Publication History

  1. Published Online: 30 APR 2008


Selection can act to maintain alleles within a population through many mechanisms that, taken together, constitute balancing selection. Over the course of primate and human evolution, balancing selection has repeatedly acted upon the species. Though ancient causes and effects may never be fully known or appreciated, current, ongoing, balancing selection can be observed in the human genome today. This is particularly true in genes related to immune response and pathogen defence, reproductive fitness and environmental stressors. In understanding balancing selection, it is possible to see the history of humanity's natural challenges as well as evolution's response.


  • balancing selection;
  • human evolution;
  • overdominance;
  • MHC;
  • human polymorphism