168 



HEREDITARY CHARACTERS 



what happens. The T stands for the tall character, S for 

 the dwarf. 



TxS 



rr/cn fist generation of hybrids 

 \ (all tall). 



IT 



(all tall) 



2T (S) 

 (all tall) 



IT 



2T(S) 



IT 



2T (S) 



IS 



IS r 2nd genera- 

 fall dwarf s)-! tion of 

 \ hybrids. 



, / 3rd generation 

 1 \ of hybrids. 



/4th generation 

 \ of hybrids. 



When two individuals, one with the tall and the other with 

 the short character, were crossed, though both characters 

 were really present in the offspring, only one of them was 

 visible to the apparent exclusion of the other. Mendel 

 called the' character that appeared the " dominant " char- 

 acter, and the character that was concealed the " recessive " 

 character. Of other pairs of characters, roundness and 

 smoothness of the seeds was dominant over the wrinkled 

 character ; colour in the seeds was dominant over whiteness ; 

 purple flowers were dominant over white flowers. 



A consideration of the diagram shows that in the second 

 generation from the cross, that is, in the offspring of the 

 hybrids, 75 per cent, showed the dominant character 

 tallness ; 25 per cent, the recessive character dwarfness. 

 The 25 per cent, recessive bred true when self-fertilised. 

 Of the 75 per cent, showing the dominant character only 

 one-third bred true ; the remaining two-thirds again gave the 



