I read (on Wikipedia) that as well as dominant and recessive genes you can have co-dominant, over-dominant and under-dominant. Could someone kindly confirm that I understand what these terms are?
Co-dominance: both alleles contribute to the phenotype (and in incomplete codominance, you get a kind of dilution, e.g. skin colour)
Under-dominance: homozygosity dominant over heterozygosity
Over-dominance: heterozygosity dominante over homozygosity
Thanks (: