CHAPTER X. 



PLUMAGE COLOR. 

 A. THE GAMETIC COMPOSITION OF THE VARIOUS RACES. 



Plumage color, like hair color, varies greatly among domesticated 

 animals. This diversity is, no doubt, in part due to the striking nature of 

 color variations, but chiefly to the fact that the requisite variations are 

 afforded in abundance. The principal color varieties, in poultry as in other 

 domesticated animals, are melanism, xanthism, and albinism. In addition, 

 poultry show the dominant white, or "gray" white, first recognized in 

 poultry by Bateson and Saunders (1902), which is also found in many 

 mammals, as, for instance, in goats, sheep, and cattle. Besides these 

 uniform colors, we find numerous special feather-patterns, such as lacing 

 (or edging of the feather), barring, penciling, and spangUng. Also, there 

 are special patterns in the plumage as a whole, such as wing-bar, hackle, 

 saddle, breast, and top of head (crest). Now, all of these color characters 

 are inherited each in its own definite fashion. 



In studying the color varieties of poultry we must first of all, as in 

 flower color (Correns, 1902), mice (Cuenot, 1903), guinea-pigs and rabbits 

 (Castle), various plants and animals (Bateson and his pupils), recognize 

 the existence of certain "factors." In poultry the factors that I have 

 determined are as follows: 



C, the color factor, absence of which results in albinism. 

 J, the Jungle-fowl pattern and coloration. 

 N (nigrum), the supermelanic factor. 

 X, the superxanthic or " buff " factor. 

 W, the graying (white) factor. 



We have now to consider how these factors are combined in birds of 

 the different races. 



1. WHITE. 



Albinos. These seem to be of two different origins:* White Cochins 

 and white Silkies. The white Silkies that I have studied have the gametic 

 formula cJnwx; i. e., they have the Jungle-fowl marking, but lack the " color 

 enzyme," supermelanic coat, the graying factor, and the xanthic factor. 



''Grays." White Leghorns and their derivatives belong to this class. 

 Its gametic formula is : CJNWx. This indicates that the race contains the 



BatesoD and Punnett (1908, p. 28) recognize three "kinds "of recessive whites that of the Silkie, that of the 

 Rose-comb bantams, and that of "white birds that have arisen in the course of our experiments. " White Cochina have 

 perhaps been one of the ancestors of Rose-comb bantams; Bate^on's new white lay recessive in the White Dorking and 

 when mated to the White Silkie throws Game-colored ofilapruig. 



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