Levels of multiallelic overdominance fitness, heterozygote excess and heterozygote deficiency (Q911516)

New concepts and results on selection models with multiple alleles are discussed. Most of the models considered by the author are one-locus systems, partially because the study of multi-locus systems effectively reduces to one-locus models when tight linkage and fitness interactions occur. The notion of heterozygote excess (or deficiency) is introduced for multi-allelic systems by referring to the eigenvalues of the corresponding genotype frequency matrix. Also the notion of heterozygote advantage is extended from its traditional meaning for two-allele viability models to the case of multiple alleles by defining four different levels of overdominance. These concepts are examined in the context of viability selection models and kin selection models.