Incomplete Dominance and Codominance (Non-Mendelian Genetics) R’R’ RR’

Incomplete Dominance –. Both dominant genes are expressed as a Incomplete Dominance – Both dominant genes are expressed as a “Mixture” of the two traits. Codominance – Both dominant genes are expressed fully in the organism

Black Chicken – BB White Chicken – WW Erminette Chicken - BW Example of Codominance

A black chicken and a white chicken are crossed, what is the probability of: White Chickens _________________________% Black Chickens __________________________% Erminette Chickens ______________________%

4) If two erminette chickens are crossed, what is the probability of: White Chickens _________________________% Black Chickens __________________________% Erminette Chickens ______________________%

Red Flowers – RR (R1R1) White Flowers – WW (R2R2) Pink Flowers – RW (R1R2) Optional Annotation Example of Incomplete dominance

6) A pink flowered plant is crossed with a white flowered plant, what is the probability of: Red Flowers _________________________% White Flowers _________________________% Pink Flowers _________________________%

7) Two pink flowered plants are crossed, what is the probability of having: Red Flowers _________________________% White Flowers _________________________% Pink Flowers _________________________%

8) What cross will produce the most pink flowers?

Practice Problems: Black Chicken – BB White Chicken – WW Erminette Chicken - BW Example of Codominance

White Fur Red Fur Roan Fur Example of Codominance

5) Roan Bull crossed with Roan Cow, what is the probability of having: Red Fur _________________________% White Fur _________________________% Roan Fur _________________________%

6) Red Bull crossed with White Cow, what is the probability of having: Red Fur _________________________% White Fur _________________________% Roan Fur _________________________%

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7) If we assume Incomplete Dominance in Tail Length (not the Manx gene) TL – Long Tail Gene (Dominant) TN – No Tail Gene (Dominant) TL TL will produce a long tailed cat TL TN will produce a short tail cat TN TN will produce a cat with no tail

White Flowers – WW (R’R’) Pink Flowers – RW (RR’) Optional Annotation Red Flowers – RR (RR) White Flowers – WW (R’R’) Pink Flowers – RW (RR’) Optional Annotation Example of Incomplete dominance

Andalusian Fowl: Black Feathers – BB White Feathers – B’B’ Bluish Gray – BB’

11) Black Andalusian Chicken crossed with a White Andalusian Chicken, what is the probability of having: Black Feathers_________________________% White Feathers_________________________% Blue-Gray Feathers_________________________%

12) Black Andalusian Chicken crossed with a Blue-Gray Andalusian Chicken, what is the probability of having: Black Feathers_________________________% White Feathers_________________________% Blue-Gray Feathers_________________________%

11) Cross two Blue-Gray Andalusian Chickens, what is the probability of having: Black Feathers_________________________% White Feathers_________________________% Blue-Gray Feathers_________________________%