No 

 50- 



40- 



30- 



20- 



10- 





 10- 



\~VI, 



0' 



F,, DxW 



\\ \J ^ M \ ■ << 



Grade, I 



16 17 



Fig. 140. Graphic presentation of the variation in grade of two races of Dutch rabbits, "dark (D) 

 and "white" (W), and results of intercrossing them. At the top is shown the gra. e distribution of 

 each uncrossed race; below is shown the grade distribution of Fi animals, of F2 amma s. an.l of anmiaLs 

 produced by back-crosses of Fi with each parent race. Note that the extracted D or AN groups diverge 

 less from each other than the uncrossed D and W groups. 



