THE CHROMOSOMES 



85 



peas, if one pair of chromosomes in the hybrid (Fi) 

 carries the contrasted elements yellow and green 

 and another pair of chromosomes of the same hybrid 

 carries the round and wrinkled elements, then, if these 

 chromosomes at the maturation period behave inde- 

 pendently, there will be four kinds of germ-cells pro- 

 duced. These four kinds will carry a yellow-bearing 

 and a round-bearing chromosome, or a yellow-bearing 

 and a w^rinkled-bearing chromosome, or a green- 

 bearing and a round-bearing chromosome, or a 

 green-bearing and a wrinkled-bearing chromosome. 



Yellow pound 

 00 



II 



\ 



I 



Po^rents 



Gpeen wrinkled 



OO 



Germ cells 



O 



Fig. 37. — Diagram to illustrate the distribution of two pairs of chro- 

 mosomes carrying two pairs of Mendelian factors, namely yellow-green 

 and round-wrinkled. The chromosome carrying the gene for yellow is a 

 black rod, that for green is a white circle; that carrying the gene for 

 round is a circle with a dot, that for wrinkled is a circle without the 

 dot. 



