Genetics of social behaviour

Social behaviour can be pretty complex at the best of times, and defining the underlying genetic events has provided a formidable challenge. In the November 15 Sciencexpress, Michael Krieger and Kenneth Ross, from the University of Georgia, describe the first clear example of a single gene affecting complex social behaviour (ScienceXpress 10.1126/science.1065247). Colony queen number in the fire ant Solenopsis invicta is associated with variations in the Gp-9 gene, such that worker ants with the B allele are associated with a single queen (monogyne social form), whereas the b allele workers are polygyne. Krieger and Ross sequenced the Gp-9 gene and show that it encodes a pheromone-binding protein. Thus, GP-9 may play a role in chemoreception by influencing worker recognition and acceptance of pheromone-producing queens. The B and b alleles are distinguished by several amino-acid changes. The Gp-9 allele variation is conserved in South American fire ants exhibiting social polymorphism. This study provides fascinating insights into the genetic basis and evolution of complex social behaviour.