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? 



Gposs.d 1 



LACT.C? 



Constitution with 

 respect to the 



GROSSULARIATA 



Duplex 



v 



Simplex 



Multiplex 



Simplex 



Multiplex 



GENOTYPE 



floi Ooi 



Ooi Ooi 



0oi 



Oof 



floi Do 



GAMETES 



a-/-^ 2). 



Ooi f) (Ooi 



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 



