Heredity — Genetics 691 



White 1 1 rr 



X 



\f RedwRR 



Pink II Rr 



F2 



X 





Pink rl Rr 



White 



Fig. 339. — Incomplete dominance when a homozygous white-flowered four- 

 o'clock (Mirabilis jalapa) is crossed with a homozygous red-flowered four-o'clock. 

 The somatic condition is shown by the flower colors; the letters show the genes 

 involved. When two pinks of the Fi generation are crossed the results are shown 

 in the Fz. 



Black 



OO 

 White-Splashed 



Fi 



B]UQ Anda\u5\an 

 o I •© 



1 



^ 



Fa 



00 



• o 



• o 



Wbite-5pla5hed 



Blue/\nda\(js'ian 



Black 



Fig. 340. — Incomplete dominance in blue Andalusian fowls. When a black 

 fowl is crossed with white-splashed-with-blue, all the Fi generation will be blue 

 Andalusian. When the latter are interbred, there are produced one-fourth white- 

 splashed-with-blue, one-half blue Andalusians, and one-fourth black in the F2 gen- 

 eration. When the white-splashed-with-blue of the Fs are interbred, only white- 

 splashed-with-blue are produced. When the blue Andalusians of the Fi are 

 crossed, they produce offspring like those resulting from the Fi. When the black 

 of the Fi are crossed with each other, only blacks are produced. The black dots 

 and circles show the factors involved in each individual. 



