x] 



The Silky Fowl 



185 



Now if femaleness be a dominant factor and can repel 

 D, forming a spurious allelomorphism with it in the way 

 suggested for the case of Abraxas grossulariata x lacticolor 

 and the Canaries, a system would be provided which would 

 fulfil all the chief conditions marked out by the experimental 

 data. 



Taking then the following allelomorphs, the occurrences 

 in the three matings which have given clear results may be 

 represented in a tabular form. 



, $, presence and absence of femaleness, a dominant 

 factor without which the zygote developes into a 

 male. 



P, /, presence and absence of the black pigmentation. 

 D, d, presence and absence of a factor which can sup- 



press or mask the development of P. 

 i. Silky ? x Brown Leghorn $ 



composition PPdd^ $ ppDD $ $ 



F l 

 composition 



composition 



females slightly males slightly 



pigmented pigmented 



PpDd<% $ PpDd$ $ 



Brown Leghorn 9 x Silky $ 



PPdd$ $ 



fi females deeply males slightly 



pigmented pigmented 



Ppdd^ $ PpDd$ $ 



3. Brown Leghorn 9 x F^ $ 



composition ppDd<% $ 



PpDd $ $ 

 (PD $ , Pd $ 



Females 

 pd^.PD$ 



Males 



pD $ . PD $ 

 pD$.Pd$ 



xametes 



offspring 



pD$.pd$ 



According to this analysis one bird in eight, namely the 

 female marked *, will be of the deeply-pigmented type. 



ceived. It would, however, fail to represent the i deeply-pigmented 9 in 

 8 birds from Brown Leghorn $ x F l <$, and would increase the expectation 

 to 2 $ in 8 birds, and this is negatived by the results of experiment. 



