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THE AMERICAN NATURALIST [Vol. LIT 



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F z Zygotes: Phenotypic Ratio 9.7 



///ustrative Experiment:- 



B. A Chemical Experiment Paralleling a Modification op 

 the Mendellan F 2 Di-hybrid Phenotypic Ratio 1:2:1:- 



2:4:2:1:2:1 INVOLVING SOMATIC BLENDING AND GENJC 



Segregation in the F x Generation 

 The ten cases described in the Series A are non-blending, in 

 which the entities 9, 3, 3, and 1 are kept intact, that is, they are 

 simply reeombined. The mono-hybrid ratio on which they are 

 based is the normal dominant-recessive 3 : 1 relation. The typical 

 blending ratio in the F 2 mono-hybrid is 1:2:1. Carrying this 

 latter ratio into the di-hybrid classification in the same manner 

 as the 3:1 ratio was carried into the 9:3:3:3 elassiti.-ation 

 gives us the following :l:2:l:2:4:2:l:2:l,a total of sixteen 

 individuals divided into 9 classes. 

 In Davenport's 3 study on the "Inheritance of Skin-Color in 

 3 Davenport, C. B., "Skin-Color in Negro-White Crosses," Pub. 188 Car. 

 Inst. Wash., 1913. 



