Simple Inheritance: Complex Inheritance: What does the word “simple” mean? (student example) What does the word “complex” mean? (student example) Simple inheritance: When there are only two alleles and one gene for a trait and one allele is dominant. The dominant allele is what we see in the phenotype Complex inheritance: When traits are determined by more factors. What you see in the phenotype is based on more complex arrangements. 1. Codominance 2. Incomplete dominance 3. Multiple alleles 4. Sex-linked 5. Environment 6. Polygenic Examples: Pea plant flower color: purple (P) or white (p) (student example) Traits more complex:Some traits are even more complex and show patterns of more than one of the complex traits: 1. Blood type: A or B are Codomiant O is recessive to both A, B and O are an example of multiple alleles 2. Cat fur color: Multiple alleles fur shade of black, brown or cinnamon. Polygenic – at least six genes work together Environment – for Siamese cats 3. Eye color in humans: Simple: Brown vs. blue Polygenic – green eyes adds another gene. Final note: They will need to know the “definitions” of simple vs. complex inheritance for the quiz and I will have it on the crossword.