MENDEL'S LAW OF HEREDITY 



But, if now two of the cross-bred black in- 

 dividuals (Fig. 16) be mated with each other, 

 the recessive white character reappears on the 

 average in one in four of the offspring (Fig. 



W ) ( W W ) Zygotes 



FIG. 18. Diagram to explain the result shown in Fig. 17. 



17). Its reappearance in that particular pro- 

 portion of the offspring may be explained as 

 follows (see Fig. 18) : The gametes which 

 united in the original cross were, one black, 

 the other white in character. Both characters 



35 



