Standard Article

Primate Evolution: Gene Loss and Inactivation

  1. Yoko Satta

Published Online: 15 FEB 2011

DOI: 10.1002/9780470015902.a0005121.pub2



How to Cite

Satta, Y. 2011. Primate Evolution: Gene Loss and Inactivation. eLS. .

Author Information

  1. The Graduate University for Advanced Studies (Sokendai), Hayama, Japan

Publication History

  1. Published Online: 15 FEB 2011


Pseudogenes are defined as genes that have lost function. However, despite the loss of function, pseudogenes can play an important role in evolution, especially when the environment changes. Owing to some environmental changes in diet or habitat, for example, pseudogenisation may be beneficial rather than deleterious for individual fitness. The human-specific pseudogenes are of particular interest, and more than 100 have been identified. These include olfactory receptors, immune function-related genes and metabolic pathway genes, which seem to be sensitive to environmental conditions. In this article, examples of environment-driven pseudogenisation are presented and the role or significance of the loss-of-function genes in the evolution of primates and humans is discussed.

Key Concepts:

  • Functional constraints maintain function of a protein and therefore maintain the conserved way of molecular evolution.

  • Relaxation of constraints can be achieved in two ways: gene duplication and environmental changes.

  • Gene duplication provides an extra copy of a functional gene, resulting in the relaxation of a functional constraint to on the gene.

  • The ‘less-is-more hypothesis’ proposed by Maynard Olson in 1999 suggests loss of function could be an advantage to organisms and also affect phenotypic or physiological changes in evolution.


  • environmental changes;
  • gene loss/inactivation;
  • single-copy pseudogene;
  • human evolution