CHAPTER XII 



HOW THE OFFSPRING COMPARES WITH THE PARENT, OR 

 DESCENT WITH MODIFICATION 



The complex nature of heredity • The offspring not like the parent • 

 Mediocrity the common lot, whatever the parentage ; regression • Some 

 offspring better and some worse than their parents • The exceptional par- 

 ent and his offspring • Progression • The exceptional offspring and his 

 parent • Reversion • Degeneracy 



Though the general process of improvement by selection is 

 simple enough, certain additional facts and principles are in- 

 volved with which the breeder needs to be acquainted in order 

 to make the selection to the best advantage. 



The complex nature of heredity. The most disconcerting 

 principle in all improvement operations lies back of the obvious 

 fact that the offspring is not like the parent. Having, as he 

 nearly always does, two parents, he could not of course be like 

 them both. The fact is, however, that for the most part he is 

 not like either one of them, nor yet is he like the two combined. 

 The most that can be said is that the offspring resembles his 

 parents, and that all his characters are to be found somewhere 

 in his parentage. 



This all means that transmission is more a matter of family 

 or general ancestral influence than it is of the two particular 

 individuals that happen to be the immediate parents. 



It has already been stated that every individual, whatever his 

 personality, transmits all the characters of the race or family 

 to which he belongs, and no others. Some of these characters 

 may not be evident in his own make-up, but if they are in the 

 blood of the family, they will be transmitted. 



All this is not saying that all characters will be transmitted 

 with the same intensity nor with the same probability of being 



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