3 4 o EXPERIMENTAL STUDY OF INHERITANCE 



The general results may be expressed in the following 

 scheme : 



D? x R<? or R? x D<? . . Parent-forms (P 1 ). 



Hybrid-offspring (F 1 ). 



D(R) . 



i R . Generation of inbred hybrids 

 (F 2 ). 



I D 



I D +2 D(R) 

 D D 3 D 



D 



iR 



i R R . (F 3 ) 



R . 



R R . (F e ) 



The result of the hybridisation is a generation (F 1 ) like the 

 dominant parent. They may be represented by the symbol 

 D(R), for they carry with them the possibility of having off- 

 spring with the recessive character ; that is to say, the recessive 

 character remains latent in the inheritance. 



When these D(R)s are inbred (self-fertilised, in the case of 

 peas) they have offspring (F 2 ), some of which resemble the re- 

 cessive parent, while others resemble the dominant parent, and 

 these occur in the proportion of 1:3. When those resembling 

 the recessive parent are inbred, they breed true i.e. they give 

 rise to a line of pure recessives. Those resembling the dominant 

 parent are all apparently alike, but their subsequent history shows 

 that they may be divided into a set which breed true to the 



