THE MENDELIAN RATIO 557 



by yA and the other by B. Now the probable combinations 

 between the two kinds of sperms and two kinds of eggs in the 



A \S B 



self-fertilization of a hybrid are represented by T /\ T . There 



A^^B 



are two chances for A and B to unite to one chance for A to 

 unite with A or B to unite with B. The probable combinations 

 and their ratios are, therefore, A A :2AB : BB or 1:2:1. 

 If the factors represented by either A or B are dominant, then 

 3 : 1 is the ratio of the dominant to the recessive offspring. 



