126 GENETICS 



selected as the tall one. The result was the same 

 in either case, showing that the character of tallness 

 is independent of the character for sex. 



When these tall cross-bred offspring were subse- 

 quently crossed with each other, or allowed to pro- 

 duce offspring by self-fertilization which amounts 

 to the same thing, 787 plants of the tall variety and 

 277 of the dwarf kind were obtained, making approx- 

 imately the proportion of 3 to 1. 



On further breeding the dwarf peas thus derived 

 proved to be pure, producing only dwarf peas, while 

 the tall ones were of two kinds, one third of them 

 "pure," breeding true like their tall grandparent, 

 and two thirds of them "hybrid," giving in turn the 

 proportion of three tall to one dwarf like their parents. 



These crosses may be expressed as follows : — 



Tall, r, X dwarf, U = tall, T(t). 



That is, tallness crossed with dwarfness equals 

 tallness with the dwarf character present but latent. 



Mendel termed the character, which became ap- 

 parent in such a hybrid, in this case tallness, the 

 dominant, and the latent character which receded 

 from view, in this instance dwarfness, the recessive. 



When now the hybrids, T(t), were crossed to- 

 gether, the result algebraically expressed was as 

 follows : — 



T -{- 1 (all possible egg characters) 

 T-\-t (a ll possible sperm characters) 

 TT+ Tt 



Tt + tt 



TT+2T(t)+tt 



