SPECIFICITY OF GENE EFFECTS 



247 



(St. semitorquata) and Ring dove, the Senegal dove and the Cape turtle dove 

 {St. capicola), the spot wing pigeon (C. maailosa) and livia, and between the 

 Grayson dove {Zenaidiira graysoni) and the common mourning dove {Zen. 

 macroura). It is possible that a hybrid substance does exist in these latter 

 species hybrids, but the same technics by which it was observed in the other 

 species hybrids failed to demonstrate its presence in them. 



Three different fractions of the hybrid substance have been demonstrated 

 in the hybrids between Pearlneck and Ring dove (Irwin and Cumley, 1945), 

 by virtue of a frequent association of each fraction with one or more antigens 



TABLE 15.2 



TESTS FOR HYBRID SUBSTANCES IN THE CELLS OF 



VARIOUS SPECIES HYBRIDS 



Antiserum to 



Fi — Pearlneck X Ring dove 



Fi — C. //zi/aX Ring dove 



Fi — St.dussumieriXRing dove. . . . 



Fi — St. humilisXRing dove 



Fi — St. orientalisXRing dove 



Fi — C. fasciataXlivia 



Fi — Mallard X Muscovy 



Fi — St. senegalensisXRing dove. . . 

 Fi — St. semitorquataXRing dove. . 



F: — Senegal X-S/. capicola 



Fi — C. tnaculosaXlivla 



Fi — C. guineaXlivia 



Fi — Zenaidura gray soniX Zen. ma 

 crmira 



Absorbed by Cells of 



Parent 1 



Parent 2 



Pearlneck 



livia 



dussumieri 



h II mil is 



orientalis 



C. fasciata 



Mallard 



St. senegalensis 



St. semitorquata 



Senegal 



C. maculosa 



C. guinea 



Zen. graysoni 



Ring dove 

 Ring dove 

 Ring dove 

 Ring dove 

 Ring dove 

 livia 



Muscovy- 

 Ring dove 

 Ring dove 

 St. capicola 

 livia 

 livia 



TLen. macroura 



Re.actions of Pa- 

 rental AND HYBRID 



Cells with the 



Respective 



Reagents 



Hy- 

 brid 



+ + 



+ + 



+ 



+ 



+ 



+ 



+ + 



























peculiar to Pearlneck. Thus one fraction called dx-A was always associated 

 in the backcross hybrids with the d-1 1 substance, dx-B seemingly was loosely 

 linked with the d-1 character and with certain others as well — thereby pro- 

 viding strong evidence that on several chromosomes of Pearlneck there are 

 duplicate or repeat genes — and dx-C was always associated with the d-4 

 antigen. The pertinent reactions which show these specificities are given in 

 Table 15.3 and are represented diagrammatically in Figure 15.2. 



Because of the constant association of the dx-A and dx-C fractions with 

 the d-11 and d-4 substances, respectively, one cannot be certain that these 

 two fractions, although antigenically distinct from the d-1 and d-11 specific 

 characters, are not simply a new specificity conferred upon the specific char- 

 acters by some sort of rearrangement of the specific substances following the 



