1. Beyond Mendelian Genetics

2. Mendel was lucky Monogenetic traits  controlled by one pair of alleles Polygenetic traits  Controlled by more than one pair of alleles e.g. skin color (7 sets of alleles)

3. Incomplete Dominance Three phenotypes WW=white flowers RR=red flowers RW=Pink flowers Kinda like mixing paint Example trait = flower color in 4 o’clock flowers

4. Codominance Three phenotypes BB=black WW=white BW=Roan (Both black and white hairs) Kinda like mixing different colored marbles Example trait = Coat color in some horses

5. Multiple Alleles More than 2 alleles for a trait Each person still has only two of those alleles FOUR phenotypes Example trait = Blood type (ABO system)

6. Multiple Alleles Example trait = Blood type (ABO system) The Alleles I A  codes for “A” antigen I B  codes for “B” antigen i  codes for neither antigen (An antigen is a receptor molecule on surface of cell used to recognize self and non-self. Non-self antigens initiate the immune response) This allele codes for “nothing” and is therefore recessive

7. Multiple Alleles Example trait = Blood type (ABO system) Genotype Phenotype I A I A Type A blood I A i Type A blood I B I B Type B blood I B i Type B blood I A I B Type AB blood i i Type O blood