C omplementary Genes 



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and if B and h produced only colorless substances, the conditions 

 would be fulfilled. By this theory, the substances produced by 

 A and a would be different chemically although they were both 



Fig. 93. Segregation in ears of maize. Lejt, ratio of 12 white : 3 purple : 

 1 red from the cross AA CC RR PrPr ii X AA CC RR prpr II. Center, a 

 ratio of 9 purple : 7 white from a cross AA cc rr PrPr X AA CC RR PrPr. 

 Right, a ratio of 9 starchy (SuSh) : 3 shrunken (Sush) : 4 sweet (suSh + 

 su sh) from the cross SiiSu shsh X susu ShSh. All these ratios are F2 ratios, 

 and the genotypes given are those of the Pi generations. In the ear at the 

 left it is difficult to distinguish between the purple and red kernels in a 

 black-and-white illustration. (Photographs by Dr. W. Brooks Hamilton.) 



yellow, so that the Ab plants would contain a different chemical 

 substance from that found in the aB and ab plants. That this 

 is not pure speculation was shown when Blakeslee dipped the 

 flowers of all his yellow-flowered plants in dilute potassium 



