122 Mendelian Sex-Factors in Man 



for sex-factors, and that " maleness " is dominant to " femaleness." 

 Individuals (zygotes) may therefore be represented as: 



Normal female iVA^ ? ? 



Colour-blind female wn ? ? 



Heterozygous (apparently normal) female l:in ? ? 



Colour-blind male nn c? ? 

 " Normal " male n cT . JV ? 

 (repulsion existing between N and j ) 



The various equations become : • 



(a) Normal female x GB male. \ 



NN%% xnn^^ =Nn^% +Nn%%. \ 



(b) Heterozygous female x " normal " (really heterozygous) male. i 

 N7ii% xn^.N% =^nn^% +Nn^% ■{■ Nn% % ->rNN%%. 



(c) Heterozygous female x GB male. \ 

 Nn% % y.nn^% =^nn^% +Nn^% -{- nn% % -V Nn% ?. ; 



{d) GB female x " normal " (really heterozygous) male. i 



If the above view of the sex-composition of Man be accepted, it of 



course follows that the sex of offspring is determined, not by the mother, ; 



but by the father, in Man. j 



I 



1 



{Received 1 Jan. 1913.) 



