D Activity is required for petal, stamen and carpel development The D gene is expressed in cells that will form petals, stamens and carpels. The D gene is required for the activity of the B and C genes.
sepal stamen petal carpel petal stamen sepal B ACCA B DD
normal D mutant sepal petal stamen carpel B B ACCA AAAA sepal * DD
The A, B and D genes are necessary for petal development. What would happen if the A, B and D genes were mis-expressed in leaves? Are the A, B and D genes sufficient to convert normal leaves into petals?
Regulatory region Petals, stamens and carpels D GENE Coding Region leaves Add Leaf regulatory region: Remove regulatory region:
A = sepals A + B + D = petals C + D = carpels B + C + D = stamens
The ABCD genes act alone, or in combination, to specify the four types of flower organs The ABCD genes are sufficient to convert leaves into flower organs The ABCD model is applicable to all flowering plants