140 



Maine Agricultural Experiment Station. 1918. 



ON THE INHERITANCE OF SWITCH COLOR. 



Since all of our parental generations had at least one mem- 

 ber of the mated pair with a black switch, it was only possible to 

 determine that this black suppressed (was dominant to) the 

 other colors, red, cream and white in the first hybrid generation. 

 In the second hybrid generation a bull with a deep orange switch 

 was produced from a black first hybrid gereration bull, - b w«" 

 Guernsey, bred back to white (Guernsey). To produce this 

 switch color a double separation of the hereditary units must 

 have taken place in the germ cells of the black first generation 

 parent bull. The black of the Aberdeen Angus and the white 

 of the Guernsey were segregated out from the fawn of the Guern- 

 sey coat. This fawn must have been further separated from the 

 dilution factor for the fawn normally present in the Guernsey 

 coat. The data for these crosses are shown in the Table VI 

 below. 



TABLE VI. 

 Inheritance of Switch Color. 



Mating. 



Character of resulting offspring. 



Sire 





Dam 













White 



White 

 Black 

 White 

 Black 

 Black 



X 



X 

 X 



X 

 X 

 X 



Black 



Brown 



White 

 White 

 Black 

 Black, red 



and 



gray 



3 



1 



12 

 4 

 9 

 3 



Black, 5 White, 2 

 White 

 Black and White 

 Black, 2 Black and 

 White, 1 White, few 

 Black 

 Black 



Black and 



White 

 black hairs 



Black 



X 



Black 







2 



Black 





White 





Black 



Fi 



White 



X 



Black 







1 



White 





White 





Black 



Fi 



White 



X 



Black and White 



1 



White 





White 







Black 



Fi 



White 



X 



White 







1 



Black, 1 Orange 





The dominance of black is easily seen from the table. 

 Black by black gave all black. White by black gave 3 black, 

 5 white and 2 black and white, showing that many animals with 

 a black switch carry the recessive white factor suppressed. In 



