96 



Heredity and Eugenics 



be re])resentcd by the letters C and P. The gametic formula 

 of the puri:>le variety is CP; the gametic formula of these 

 particular white varieties is cp. If either C or P is absent 

 from the zygotic formula of F^ then the zygote is white as 

 is shown in the diagram. 



DIAGRAM ILLUSTRATING INHERITANCE OF PURPLE ALEURONE 

 CELLS IN MAIZE WHEN TWO FACTORS ARE CONCERNED 



The formula of the purple is therefore CCPP, but whites 

 with formulas CCpp, ccPP, and ccpp may exist. When the 

 whites have formulae CCpp or ccPP they give monohybrid 

 ratios when crossed with the purple, but when they have 

 the formula ccpp a dihybrid results. 



This illustration shows both why one cannot tell just 

 how complex a character is, and why characters essential 

 to the species cannot be analyzed. 



These cases of Mendelian inheritance are types. Other 



