PLUMAGE COLOR. 



75 



2. SILKIE X WHITE LEGHORN. 



By hypothesis this cross is between cJnwx and CJNWx. The first 

 generation should give the zygotic formula CcJ^NnWwx^, or, more simply, 

 CcJ^NnWw. This formula resembles closely that of the White Leghorn, 

 except that the coloring and graying factors and that for supermelanism 

 are all heterozygous and hence diluted; only the Jungle coloration remains 

 unchanged. Actually, the first generation yielded a lot of white birds Uke 

 the Leghorn, but with this difference, that, as the males became mature, 

 they gained red on the wing-bar and to a slight extent on the lacing of the 

 saddle. The females gained a faint blush of red on the breast. Thus red 

 appeared, in small amount, in just those places in the respective sexes 

 which are red in the Jungle-fowl. The explanation of its appearance that 

 I have to suggest is that, both on account of the diluting of the super- 

 melanic coat and of the graying factor, the red of the undiluted underlying 

 Jungle coloration is revealed. 



Since the hybrids are heterozygous in respect to 3 pairs of characters, 

 when segregation occurs each parent produces 8 kinds of gametes, as fol- 

 lows: CJNW, CJNio, CJnW, CJnw, cJNW, cJNw, cJnW, cJnw. When 

 both parents produce these 8 kinds of gametes we may expect, in 64 

 offspring, the proportions of the several types shown in table 59. 



Table 59. Probable frequency in 64 progeny. 



While, if the progeny were all to survive to maturity, we might expect 

 to get the proportions of white and of white-and-red progeny called for, 

 yet, since the red color appears in most cases at an age after the chicks are 

 described, it will be necessary in comparing experience with calculation to 

 combine the first two classes as whites. We then find the proportions 

 given in table 60. 



Table 60. 



