HUMAN INHERITANCE 195 



netic constitution AaBh be mated to another indi- 

 vidual of like constitution (AaBb), then each will 

 contain four kinds of germ cells, viz., AB, Ah, Ba, 

 and ah. The sixteen possible combinations formed, 

 if any sperm may fertilize any egg^ are shown in 

 figure 75. 



These sixteen individuals fall into four groups 

 according to whether they have both A and B, or 



Mating of blood group AaBb to same AaBb 



Ege= AB 



a 



B Ab 



a 



b 



jeTTa 



AB 



aB 



Ab 



ab 



AB 

 AB 



a B 



aB 



m. 



aB 



a 



m 



Ab 

 AB 



a b 



aB 



IE 



a b 

 a b 



Fig. 73. — Diagram illustrating the sixteen classes of indi- 

 viduals when two members of the blood group AaBa mate. 

 There are four classes of individuals produced, indicated by 

 the circles, lines, squares, and absence of A and B. 



