Altruism can proliferate through population viscosity despite high random gene flow

PLoS One. 2013 Aug 19;8(8):e72043. doi: 10.1371/journal.pone.0072043. eCollection 2013.


The ways in which natural selection can allow the proliferation of cooperative behavior have long been seen as a central problem in evolutionary biology. Most of the literature has focused on interactions between pairs of individuals and on linear public goods games. This emphasis has led to the conclusion that even modest levels of migration would pose a serious problem to the spread of altruism through population viscosity in group structured populations. Here we challenge this conclusion, by analyzing evolution in a framework which allows for complex group interactions and random migration among groups. We conclude that contingent forms of strong altruism that benefits equally all group members, regardless of kinship and without greenbeard effects, can spread when rare under realistic group sizes and levels of migration, due to the assortment of genes resulting only from population viscosity. Our analysis combines group-centric and gene-centric perspectives, allows for arbitrary strength of selection, and leads to extensions of Hamilton's rule for the spread of altruistic alleles, applicable under broad conditions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms
  • Altruism*
  • Cooperative Behavior
  • Evolution, Molecular
  • Gene Flow*
  • Genetic Loci / genetics*
  • Human Migration
  • Humans
  • Models, Genetic
  • Population Dynamics
  • Selection, Genetic*

Grant support

This project was partially supported by CNPq, under grant 480476/2009-8 and by the Center for Natural and Artificial Information Processing Systems of the University of São Paulo (NAP CNAIPS-USP). No additional external funding has been received for this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.