expressed the same callipyge phenotype if they inherited the mutated allele from Solid Gold and a wildtype allele from their mother, which would result in a Cpat/Nmat genotype. Offspring with genotypes such as: Cpat/Cmat, Npat/Nmat, and Npat/Cmat did not express the callipyge phenotype. Gillespie model Population Geneticist John H. Gillespie established the following model: Where h is the heterozygote effect and s is the recessive allele effect. Thus given a value for s (i.e.: 0<s<1), h can yield the following information: For the case of sickle cell anemia the situation corresponds to the case h<0 in the Gillespie Model . See also Dominance versus overdominance Polar overdominance Underdominance Outbreeding depression References References Classical genetics Genetics concepts