THE DETERMINATION OF SEX 



217 



Doncaster and Raynor, in 1908, published the results 

 of various crosses between these two varieties which 

 demonstrate clearly that sex is a Mendelian character 

 and that, in this instance, maleness is homozygous 



and femaleness heterozygous with the determiner 



* 



KEY TO SYMBOLS 



PHENOTYPE 



GROSS.C? 



GROSS, c? 



LACT.6 1 



lOnstitution with 

 respect lo the 



GROSSULARIATA 



Duplex 



Simplex 



Nulliplex 



Simplex 



Nulliplex 



.ENOTYPE 



001 Ooi 



Ooi Ooi 



Qoi floi 



00i So 



Ooi Oo 



GAMETES 



FIG. 67. Key to the symbols employed in Figures 68-71. The outline 

 symbols represent samples of the autosomes or somatic chromosomes. 

 The black symbols stand for the "extra" or sex chromosomes. O 

 above a black symbol indicates the grossulariata factor linked with a 

 sex chromosome. The variety lacticolor occurs whenever the grossu- 

 lariata factor is absent. 



for maleness linked with the factor producing the 

 variety grossulariata. A study of Figures 67-71 

 will make this case clear. Outline symbols represent 

 ordinary chromosomes or autosomes, several of which 

 are omitted for sake of clearness. The black sym- 

 bols represent sex chromosomes. The letter G placed 



