THE PROBLEM OF INBREEDING 131 



TABLE 4 



WORKING TABLE USED m CALCULATING THE COEFFICIENTS 

 OF INBREEDING FOR PEDIGREE TABLE VI 



100(2) aK 



Z z = *-i = 25 per cent, 



8 



100(6) K 

 Z 3 = *-* = 37.5 per cent. 

 16 



From these values it is seen that in the first four 

 ancestral generations the cow Bess Weaver is 

 37.5 per cent inbred. This is a perfectly definite 

 figure, directly comparable with similar constants 

 for other animals. Of course, if we were to go 

 back more generations we should find Bess Weaver 

 still more inbred, that is, the coefficients would 



be zero, or in other words that in the first ancestral generation, con- 

 sidered alone, there is no inbreeding will be cleared up, if it strikes 

 the reader as paradoxical, by a reconsideration of the general prin- 

 ciple numbered 5 on p. 110. The point of course is that it is impos- 

 sible to say whether the parents are or are not related to one another 

 until something is known of their parentage, or in other words, until 

 a second ancestral generation is considered. 



