Selfish genes: a green beard in the red fire ant

  title={Selfish genes: a green beard in the red fire ant},
  author={Laurent Keller and Kenneth G. Ross},
A ‘green-beard’ gene is defined as a gene that causes a phenotypic effect (such as the presence of a green beard or any other conspicuous feature), allows the bearer of this feature to recognize it in other individuals, and causes the bearer to behave differently towards other individuals depending on whether or not they possess the feature. Such genes have been proposed on theoretical grounds to be agents mediating both altruism and intragenomic conflicts,, but until now few, if any, of these… 

Red ants with green beards

Keller and Ross (1998) have produced what appears to be the first experimental evidence for a green beard gene in polygynous colonies (colonies with many queens) of the so called red fire ant, Solenopsis invicta.

Evolutionary biology: Green beard as death warrant

'Green beard' genes are theoretical constructs that cause their bearer to display a distinctive trait, fancifully named a green beard, and in this case, if queen ants lack the gene they are executed by workers that carry it.

Altruism through beard chromodynamics

This work model the green beard effect and finds that if recognition and altruism are always inherited together, the dynamics are highly unstable, leading to the loss of altruism, whereas if the effect is caused by loosely coupled separate genes, altruism is facilitated through beard chromodynamics in which many beard colours co-occur.

Potential cause of lethality of an allele implicated in social evolution in fire ants

Data are consistent with the hypothesis that the Lys151 residue in GP-9 protein confers the deleterious effects of the b allele in homozygous condition, possibly by impairing the protein’s function through interference with ligand binding/release or hindrance of dimer formation.

Green beards in the light of indirect genetic effects

This work uses models of indirect genetic effects (IGEs) to find the minimum correlation between the signaling and altruistic trait required for the evolution of the latter, and shows that this correlation threshold depends on the strength of the interaction, as well as the costs and benefits of the altruistic behavior.


This work develops population genetic models that formally examine selection of greenbeard phenotypes under the control of different loci and finds that, in many cases, greenbeards are not outlaws because selection for or against the greenbeard phenotype is the same across all loci.

Genetics: A social rearrangement

A large-scale analysis of the genomic region involved in fire ant polymorphism is presented and, surprisingly, the various aspects of this polymorphism are found to be governed by a non-recombining supergene occupying half a chromosome.

Altruism, Spite, and Greenbeards

It is shown how recent work has resolved three key debates, helping clarify how Hamilton’s theoretical overview links to real-world examples, in organisms ranging from bacteria to humans.

The role of Gp-9 in regulating social behavior in fire ants

It is sought to show how a relatively small number of the b all le carrying workers are sufficient to elicit polygyny behavior and that queen effects do not influence the acceptance of supernumerary queens, and to show that single nucleotide substitutions at the Gp-9 locus are not sufficiently associated with polygyne behavior.

Molecular Variation at a Candidate Gene Implicated in the Regulation of Fire Ant Social Behavior

No single b-like residue is completely predictive of polygyne behavior and, thus, potentially causally involved in its expression, so naturally occurring variation at Gp-9 in fire ants is described, and several unique alleles bearing various combinations of b- like and B-like codons are found.



Gestational drive and the green-bearded placenta.

  • D. Haig
  • Biology, Psychology
    Proceedings of the National Academy of Sciences of the United States of America
  • 1996
Green-beard effects have many formal similarities to systems of meiotic drive and, like them, can be a source of intragenomic conflict.

Phenotypic Basis of Reproductive Success in a Social Insect: Genetic and Social Determinants

There is a counterintuitive relation between the potential and realized reproductive success of queens in multiple-queen societies of this ant, which is an unusual example of genotype-environment interaction in gene expression in which the environmental component is the social environment.


Patterns establish that a single mendelian gene influences queen reproductive role in S. invicta and that this gene uniformly is under strong directional selection in the polygyne social form only.

Strong selection on a gene that influences reproductive competition in a social insect

The existence of a single mendelian factor that strongly influences success in reproductive competition in multiple-queen societies of an ant is reported and a mechanism by which variation is maintained at this gene despite the presence of strong directional selection is proposed.

The genetical evolution of social behaviour. I.

On the relationship between queen number and fecundity in polygyne colonies of the fire ant Solenopsis invicta

Investigating the reproductive status of individual queens in relation to the number of queens in polygyne colonies of Solenopsis invicta Buren found that the inverse relationship between queen number and fecundity results from mutual inhibition among queens, possibly involving pheromones, rather than reduced nutrition through lower worker/queen ratios.

The population dynamics of maternal-effect selfish genes.

We use population genetic methods to describe the expected population dynamics of the selfish-gene chromosomal factor, Medea (maternal-effect dominant embryonic arrest), recently discovered in flour

Impact of migration and fitness on the stability of lethal t-haplotype polymorphism in Mus musculus: a computer study.

It is suggested that small deme size and interdemic migration alone do not explain the observed t-haplotype frequencies, and there is no stable, low-level t-polymorphism, rather wild populations are in one of two stable states characterized by extinction of the t- Haplotype and a high t- haplotype frequency, respectively.

Kin selection and frequency dependence: a game theoretic approach

In this view, Hamilton's rule is basically correct for describing kin selection, and most deviations from it are due to the distinct process of synergistic selection.