C omplementary Genes 



327 



hybrid ratio genotypically. As to external appearance, however, 

 it so happens that the interactions of C and p, of c and P, and of 



Fig. 91. Segregation of colored grains in ears of maize. Left, an ear 

 segregating 3 colored {ICC -\-2Cc) : 1 noncolored (cc). Right, an ear 

 segregating for the color-inhibiting gene, /, as well as for C, thus produc- 

 ing the ratio : 13 noncolored (9C7-j-3c7-f-lcO :3 colored (CO. These 

 ears are also segregating for other genes, as sugary. (Photogi'aph by Dr. 

 W. Brooks Hamilton.) 



c and p all produce flowers that are indistinguishable in appear- 

 ance so that the normal 9:3:3:1 ratio becomes modified to 

 9 : 7. On a chemical analogy, C might produce a colorless 



