| Genetics |  |
Incomplete dominance
The dominance of one allele over an other is not always complete. Sometimes one can distinguish a homozygotic individual from a heterozygotic one. One clear example of this one can find in the Four O-Clock flower, Mirabilis. Here the red color is incomplete dominant over the white. Heterozygotic flowers get at color in between red and white - they become pink. This is called incomplete dominance.
If one crosses a red and a white Mirabilis all the offspring will have pink flowers. If one crosses two pink flowers we get the following breeding chart:
_______________________________________ | | | | | | fr | fw | |____|______________|_________________| | | | | | fr | frfr | frfw | | | red | pink | |____|______________|_________________| | | | | | fw | frfw | fwfw | | | pink | white | |____|______________|_________________|
We then get the splitting ratio 1 red : 2 pink : 1 white - 1:2:1.