^ 1 1 



o 

 O 



62 w ft'-^k ^a iin oa 3t <7) iitii jg - Si 



Gametic Kepdlsion, 



The case in wliicli more sufficient data have been obtained up to the present 

 is that of the normal-yellow repulsion. Relating to the reduplication under 

 consideration, over 70 famihes involving more thaa 20,000 individuals were 

 reared, certain famiUes of them being carried up to r4 generation. The hetero- 

 zygotes (AaBb) were, in the course of experiments, also crossed with the double 

 recessives (aabb) reciprocally. The gametic series tlius revealed were 



AB Ab aB ab 



2 : 1 



3 : 1 

 1 



The recombination of these gametic forms will re?ult in the zygotic series 



A-B- A-b- a-B- a-b- 

 2:1:1:0 



So far as the experiments have been cj,rrie3 on up to F.^ in the straight 

 direction, the case is hardly distinguishable from an ordinary case of complete 

 repulsion that occurs alike on both sexes. In the present case, however, F^ A-B- 

 form is not even in its zygotic constitution but is composed of various biotypes 

 which may give the offspring in various combinations of F^ forms — I.e. the result- 

 ing F3 families can be grouped into four classes as follows : 



Class (a) involving 3 zygotic forms, A-B-, A-b-, a-B- ; 

 „ (b) „ 2 „ , A-B-, A-b- ; 



„ (c) „ 2 „ , A-B-, a-B- ; 



(d) „ only A-B- form. 



F2 A-b- and a-B- individuals are each composed of two groups, one breed- 

 ing true to their parents, while the other producing aabb animals in addition to 

 those of the parental type. 



All this is beyond explanation if the ordinary complete repulsion be supposed 

 as the case, but it can easily be accounted for if the gametic series above given 

 was assumed. More positive evidence for such dimorphism of gametic series 

 has been actually obtained from the crosses between the heterozygote and the 

 double recessive. 



