Duck: Short-Horn Color Inheritance 



69 



GENETICALLY PURE RED 



Figure 6. Pure reds bred to pure reds should always produce offspring of the same 

 color. The contradictory results sometimes obtained from using the data contained in the 

 herd books of the cattle breeding associations are caused by the classification as red of such 

 animals as that shown in Figure 5. Genetically the two animals are not the same, and this 

 tact would be shown by differences in the color of their offspring. 



PEDIGREE OF DUKE OF GLENSIDE 813884— RED 



Sire 



Dam 



General Clay 255920 

 Red and White 



Lady Favorite (Imp.) 

 634158 Red 



r Duke Buttercup 

 J 160769 Roan 

 I Mamie Clay 2nd 

 ^ V48-342 Red and White 



Coral Favorite 

 634157 Roan 



Lady Grace 

 593355 Roan 



and genetically are really red-and- 

 whites. Tracing 1743 matings of this 

 character, almost fifteen per cent of 

 them were registered as red-and- 

 white (See Table III). The logical 

 genetic explanation for the appearance 

 of these individuals is a heterozy- 

 gous condition of the white parent 

 for the roan extension factor (E). 

 The absence of black-and-white indi- 



viduals appearing in the Iowa work 

 is due to the fact that the black of the 

 Galloway acts difterently than the red 

 of the Short-Horn toward assuring a 

 pied pattern in the phenotype ; this is 

 probably due to the presence of some 

 inhibiting factor associated with Gal- 

 loway black. 



That the red of the Short-Horn can 

 also carrv the roan extension factor is 



