MENDELISM 11 



Observe ! the recessive character (in Fij) has been 

 inherited from a hybrid parent which looked exactly like 

 the original dominant parent ; it follows, therefore, that 

 this recessive character must have been present, though 

 hidden, in the hybrid, and that the hybrid is really different 

 from the original parent, though like it in appearance. 

 This difference may be expressed in the diagram by letting 

 D[R] represent the hybrid, putting the R in brackets, to 

 show that the recessive character is present, though latent, 

 and by mere inspection quite unrecognizable. In other 

 words, the hybrid has a double nature : the dominant and 

 the recessive factors are both present in the hybrid, though 

 only the dominant shows. The hybrid is an "impure 

 dominant," and does not breed true to the dominant 

 character. The fact that pure dominants and pure 

 recessives breed true to their respective characters is 

 indicated thus — 



D x D R x R 



and 



D R 



You will see that it is necessary to amend the diagram 

 on page 10 in order to indicate that the Fj generation 

 consists of impure dominants, thus — 



D x R 



D[R] 



ill i 



D D D R 



Thus we cannot always tell what the offspring will be 

 like from simple inspection of the parents, for tall plants 

 may produce dwarfs. The results are not what would be 

 looked for in accordance with the ordinary view of heredity 

 that "like produces like." 



