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TYPES OF MENDELIAN HEREDITY 



the factor for white both affect the plant in which they 

 occur. In this and in similar cases the Fo ratio of 

 1 :2 : 1 is obtained, because it is possible to distinguish 

 the pure red and the pure white from the heterozygous 

 plants. 



Fig. 14. — Diagram to illustrate the cross between a red and a white 

 flowered Mirabilis jalapa (4 o'clock), which produces a pink, intermediate 

 heterozygote. 



The Andalusian fowl is a similar case. When 

 certain races of black are bred to certain races or 

 kinds of ''white" the hybrid is slate ''blue" in color. 

 These blue birds, called Andalusians, when inbred, 

 give one black to two blue to one white. Blue is 



