246 HEREDITY AND ENVIRONMENT 



ters. The seven contrasting characters of his 

 peas could be represented as follows: 



Seeds, round (A), or wrinkled (a) ; yellow 

 (B), or green (b) ; with gray seed 

 coats (C), or white seed coats (c). 



Pods, green (X)), or yellow (d) ; inflated 

 (E), or constricted (e). 



Habit, tall (F), or dwarf (/). 



Flowers, axial (G), or terminal (g). 



It is possible for one plant to have all of 

 these dominant characters or all of the reces- 

 sive ones, or part of one kind and part of the 

 other. The inheritance formula of a plant 

 having all seven of the dominant characters is 

 ABCDEFG; of one having all of the recessive 

 characters abcdefg. When two such plants 

 are crossed the inheritance formula of the hy- 

 brid is AaBbCcDdEeFfGg, and since the 

 dominant and recessive characters (or rather 

 determiners of characters) represented by 

 these seven pairs of letters separate in the for- 

 mation of the gametes, and since each separate 

 determiner may be associated with either mem- 

 ber of the six other pairs, the number of possi- 

 ble combinations of these determiners in the 



