title: Genetic polymorphisms between altruism and selfishness close to the Hamilton thresholdrb=c.
abstract: Genes that in certain conditions make their carriers altruistic are being identified, and altruism and selfishness have shown to be heritable in man. This raises the possibility that genetic polymorphisms for altruism/selfishness exist in man and other animals. Here we characterize some of the conditions in which genetic polymorphisms may occur. We show for dominant or recessive alleles how the positions of stable equilibria depend on the benefit to the recipient,b, and the cost to the altruist,c, for diploid altruists helping half or full sibs, and haplodiploid altruists helping sisters. Stable polymorphisms always occur close to the Hamilton thresholdrb=c. The position of the stable equilibrium moves away 0 or 1 with both increases inc, the cost paid by the altruist, and increasing divergence from the Hamilton threshold, and alleles for selfishness can reach frequencies around 50%. We evaluate quantitative estimates ofb,candrfrom field studies in the light of these predictions, but the values do not fall in the regions where genetic polymorphisms are expected. Nevertheless, it will be interesting to see as genes for altruism are discovered whether they are accompanied by alternate alleles for selfishness.
authors.affiliation: School of Biological Sciences , University of Reading , Whiteknights, Reading RG6 6AS , UK.
authors.forename: Richard M
authors.identifier: 0000-0001-6828-3543
authors.initials: RM
authors.lastname: Sibly
authors.affiliation: Department of Mathematics and Statistics , University of Reading , Whiteknights, Reading RG6 6AX , UK.
authors.forename: Robert N
authors.initials: RN
authors.lastname: Curnow
keywords: Hamilton's rule; population genetics; stable polymorphisms