The theory of kin selection.

Constructs a theoretical framework within which various models relating to kin selection can be placed in perspective. To evolve by kin selection a genetic trait expressed by one individual (actor) must affect the genotypic fitness of one or more other individuals who are genetically related to the actor in a non-random way at the loci determining the trait. Comments on this definition range over altruism, parental care and social selection. Relationships are shown between kin selection and frequency-dependent selection, individual selection and group selection. Discussion continues to include formal relations of the family-structured model to the identity coefficient model; parental manipulation; effects of inbreeding; and Hamilton's rule (for spread of an altrustic trait) and inclusive fitness.-P.J.Jarvis