Incomplete Dominance & Codominance

Incomplete Dominance red white pink Defined: When neither allele is dominant and the alleles blend together No recessive allele More than 2 different phenotypes can occur Ex: Many flower colors

List the genotypes. 4RW List the phenotypes. 4 Pink Example: Cross a homozygous red 4 o’clock flower (RR) with a homozygous white flower (WW). List the genotypes. 4RW List the phenotypes. 4 Pink W W R W R W R pink pink R W R W pink pink

List the genotypes. 2RW, 2WW List the phenotypes. 2 Pink, 2White R W R Example: Cross one heterozygous pink (RW) 4 o’clock flower with a White flower (WW). List the genotypes. 2RW, 2WW List the phenotypes. 2 Pink, 2White R W R W W W W pink white R W W W pink white

Codominance red white roan Defined: When both alleles are dominant and equally expressed The colors do NOT blend together, but are equally seen Ex: Cattle Coat Red cow x White cow = Roan Cow Ex: Human Blood types Type A x Type B = Type AB red white roan

Multiple Alleles Defined: More then 2 alleles control a trait Ex: Blood Type has 3 alleles Dominant A allele Dominant B allele Recessive O allele A and B allele are equally codominant

Ex: Cross Jason who is homozygous for type A blood with Maria who is homozygous for type B blood. List the genotypes. 4AB List the phenotypes. 4 type AB blood B B A A B A B A B A B

Ex: Cross Mike who is heterozygous for type A blood with Lisa who is heterozygous for type B blood. List the genotypes. 1AB, 1Ao, 1Bo, 1oo List the phenotypes. 1 type AB blood 1 type A blood 1 type B blood 1 type o blood Probability of Heterozygous individual? 75% B o A o A B A o B o o o