1909.] The Theory of Ancestral Contributions in Heredity. 221 



Table II. 





Grandparent 



s. 





Offspring. 



DU. 



Da. 





+ 





DL>. 



Til? 



XYXV. 



4 



3 



1 





4 

 4 



— 

 — 



1 



6 



2 



— 



3 





1 

 X 



3 



1 



9 



9 





2 



2 





4 





• 13 



10 



1 



2 



1 



l 



3 



1 



8 



14 



2 



o 

 Z 





2 





o 



1 



4 



1 



l 



3 





4 





12 



16 



4 



l 



2 



1 



3 



1 



10 



28 



10 



l 



1 



2 



2 



2 



2 



14 



8 



l 





3 



1 



3 





2 



2 





4 





4 





4 



8 



4 





3 



1 



3 



1 



4 



16 



12 





2 



2 



2 



2 



1 



10 



13 





1 



3 



1 



3 





2 



6 







4 





4 







1 



Now Table II may be examined from several standpoints. We may 

 first consider the gametic constitutions of the grandparents and of the 

 offspring. Thus we have : — 



No. of DD's in grand- 

 parentage. 



Percentage of DD's in 

 offspring. 



4 



100 



3 



67 



2 



41 



1 



22 



• 



11 



In other words, the constitution of the grandparentage substantially 

 modifies the offspring ; there exists in this sense an " ancestral contribution " 

 to the heritage. 



Of course the gametic constitution EE follows precisely the same system 

 of percentages, and is again influenced by ancestry. 



If, however, we take the gametic constitution DE in such a population 

 we find — 



No. of DE's in grand- 

 parentage. 



Percentage of DE's in 

 offspring. 



4 



50 



3 



50 



2 



50 



1 



50 







50 



