BREEDING 



119 



In the third ancestral generation, as shown in Fig. 56, 

 birds A, B, C, D, each appear twice and the number of 

 ancestors of K is thereby reduced one-half. That is to say, 

 K has only four different individuals as grandparents 

 instead of the supposedly normal number, eight. This is 



FiQ. 56 

 E 



A 

 B 



K 



Illustrating inbreeding but not line breeding. 



the mating of relatives and is, therefore, inbreeding. Because 

 no one of these birds appears in the pedigree of K oftener 

 than any other of the same generation, no line breeding has 

 been done. 



Fig. 57 



^ \ c 



K 





Illustrating inbreeding that is line breeding. 



In Fig. 57 the number of ancestors is also reduced by half 

 and the intensity of the inbreeding of L is exactly the same as 

 that of K in Fig. 56. A notable difference, however, arises in 

 the fact that each blood line of L runs back to ^ as a sire in 

 Fig. 57. L is therefore said to be line bred with reference to A. 



