32 



MENDELISM 



CHAP. 



On Mendel's view there was a factor corresponding to 

 the dominant character and another factor corresponding 

 to the recessive character of each alternative pair of unit- 

 characters, and the characters were alternative because no 



Fig. 4. 

 Fowls' combs. A, pea; B, rose; C, single; D, walnut. 



gamete could carry more than one of the two factors 

 belonging to the alternative pair. On the other hand, 

 Mendel supposed that it always carried either one or the 

 other of such a pair. As experimental work proceeded, 



