CHAPTER VII 



SEGREGATION AND DOMINANCE 

 1. Methods of Studying Heredity 



Modern studies in heredity have been pursued 

 principally in three directions : first, by microscopical 

 examination of the germ-cells ; second, by statistical 

 consideration of data hearing upon heredity ; and 

 third, by experimental breeding of animals and 

 plants. 



The first two of these methods of approach have 

 already been touched upon as well as experimental 

 breeding with reference to "pure lines." In the 

 present chapter attention will be directed to a con- 

 sideration of experimental breeding with reference 

 to hybridization, that is, breeding from unlike par- 

 ents, a process which Jennings characterizes by the 

 expressive phrase, "the melting-pot of cross-breed- 

 mg. 



2. The Melting-pot of Cross-breeding 



Hybridization, or cross-breeding, as formulated 

 by Galton (1888), results in one of three kinds of 

 inheritance, namely, blending, alternative, or par- 

 ticulate. 



120 



