SEX-LIMITED INHERITANCE IN POULTRY 15 



TABLE 10 



Fi {Broim Leghorn cf X Dark Brahma ? ) X F, {Broivn Leghorn cT X Dark 



Brahma ?) 



Inheritance of hackle lacing 



Gametes 



/W w 



Iw 



JWw W 50 per cent of the 



^ \ww w males with white 



hackle; 50 per cent 

 with red; same 

 with the females 



Returning to the males, the mheritance of the color of the wing- 

 bar has to be considered. By hypothesis, the sperms of the hy- 

 brids carry in equal numbers, red-bar and no red (white) bar: 

 while the eggs all carry red-bar. Two kinds of males with the 

 same external appearance are, accordingly, to be expected; 

 namely, duplex and simplex red-bar. All offspring recorded had 

 red wing-bar, but in some cases less strongly developed than in 

 the pure Brown Leghorn race. In all cases, then, the results 

 agree with hypothesis. 



The matings of hybrids of the reciprocal cross (viz., Dark 

 Brahma d" and Brown Leghorn $ ) yielded few offspring, only two 

 males and four females; but the results are not without interest. 

 By hypothesis, in hybrid males half of the sperms have the deter- 

 miner for white lacing and the remainder for red lacing ; also half of 

 the sperms have the determiner for red wing-bar and half lack it. 

 All hybrid pullets carry the determiner for white lacing in half 

 of their eggs and for white wing-bar in half of their eggs. It 

 follows that of male offspring all should have white lacing, and 

 half should have red and half white wing-bar. Of the female 

 offspring, on the other hand, half should have red and half white 

 lacing. The formulae are as given in table 11. Actually each 

 class is represented in exactly the expected proportions. 



