Work sheet on co-dominance and incomplete dominance

Co-Dominance Up until now you have been working on the idea that one strong gene hides a weak gene; this is called simple dominance. Now we are going to learn about two other patterns of inheritance. x R W RW Co-dominance: When you cross 2 pure lines and the F1 show equal expression of both traits. Red flowers x White flowers gives you red and white stripes

Incomplete Dominance Incomplete dominance: when you cross 2 pure lines and the F1 blended expression of both traits. Red flowers x White flowers gives you pink flowers. x R W RR RW WW

Classic phenotypic ratio In both cases, because the alleles are equal strength you use capital letters for each allele. In both cases if you cross the F1 you get a classical phenotypical ratio of 1 : 2: 1 or 1: 2: 1 Red: Striped: Red Red: Pink: Red

practise 1. Four O’clocks are flowers that are renowned for incomplete dominance. What would the offspring look like(Phenotype)if you crossed: a) a red flower with a pink flower b) a red flower with a white flower c) a white flower with a pink flower d) 2 pink flowers Let: R=red, W=white Find the phenotypic ratio of each F1 generation Given: a) RR x RW b) RR x WW c) WW x RW d) RW xRW F1: 1 : 1 100% 1 : 1 1 : 2 : 1 Red:Pink Pink Pink : White Red : Pink : White