IV 



INSEPARABLE EFFECTS 



An early example of the difficulty of separating the 

 characters produced by different materials or factors, as 

 they may now be called, occurred in Professors Bateson's 

 and Punnett's experiments on the inheritance of fowls' 

 combs. The experiments are detailed in the second and 

 third " Reports to the Evolution Committee of the 

 Royal Society," and summarized in the fourth. 



When rose-combed fowl were mated with single- 

 combed, the hybrids were all rose-combed. Thus rose 

 comb seemed dominant to single comb ; and, when the 

 hybrids were mated with each other, this inference was 

 confirmed, for their progeny's combs were roses and 

 singles in the ratio 3 : 1 (actually 695 and 235). 



Again, when pea-combed fowl were mated likewise 

 with single-combed fowl, the hybrids were all pea- 

 combed. Thus pea comb also seemed dominant to 

 single comb ; and this inference also was confirmed 

 when the hybrids were mated with each other, for their 

 progeny's combs were peas and singles in the ratio 

 3 : 1 (actually 567 and 210). 



Two different dominants to one and the same reces- 

 sive was a new phenomenon having no parallel in 

 Mendel's experiments, in which each dominant had only 



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