No. 644] INHERITANCE OF PLUMAGE COLOR 



245 



The offspring of the purebred Light Brahma male by buff 

 females were much whiter than the chicks from the first 

 male. Only one of the thirty- seven showed the dark head 

 spot characteristic of Light Brahma chicks and all were 

 of a clear dead white, lacking even the yellowish tinge 

 characteristic of most white chicks in the down. As 

 adults these birds were very similar to the first lot. The 

 amount of black in hackles, tails and wings was about 

 intermediate between the amount present in the Colum- 

 bian parent and the absence of black in pure white birds. 



The first generation hybrid chicks were crossed in two 

 ways. The Fi Columbian females were backcrossed to 

 a purebred Buff Plymouth Rock male ; the Fi buffs were 

 bred inter-se. The results of these matings are presented 

 in Tables II and III. 



Pure Buff Malet. 



From the backcross of F^ Columbian females with a 

 buff male equal numbers of buff and white chicks re- 

 sulted, a clear monohybrid segregation. Evidently one 

 factor determines the difference between white and buff, 

 and from the F^ results it is clear that white is the domi- 

 nant allelomorph. This factor is however sex-linked, since 



