68 



EVOLUTION AND GENETICS 



(Fi), contains both sets of these elements; it is 

 GgJVw. These represented in pairs are: 



G W 



g w 

 Now when the germ-cells of this hybrid mature the 

 members of one of the pairs behave independently 

 of the members of the other pair. Consequently four 

 kinds of germ-cells are possible, namely, GW , Gw, 

 gJVj gw {fig. 25) . There will be four kinds of egg- 



Yellov/ Round 



green wrinkled 



Yel]ow(^reen) Round(wrinkled) 



.o. 







Yellov/ 

 green 



Round 

 wrinkled 



01* 



Yellow 

 green 



wrinkled 

 Round 



o 



Q 



Fig. 25. — Diagram to shoM- the independent segregation of the 

 two pairs of factors, yellow-green and rouncl-wrinivled. 



cells in the hybrid and four kinds of f)ollen grains. 

 Chance fertilization of any egg-cell by any pollen 

 grain will give sixteen classes of individuals, as 

 show^n in figure 26. 



There will be, as inspection of the table shows, 9 



