64 



GENETICS IN RELATION TO AGRICULTURE 



tion in each pair of chromosomes such that the particular member of one 

 pair which went to a given pole of the reduction spindle would have no 

 influence on the distribution of the members of any other pair. Such 

 independent distribution of chromosomes appears to be actually the type 



FIG. 31. Diagram showing consequences of independent segregation of chromosomes in 



Drosophila ampclopkila. 



followed in reduction. As a consequence the germ cells contain various 

 combinations of chromosomes with respect to their original parental deri- 

 vation. In Fig. 31 the types of combinations of maternal and paternal 

 chromosomes and their mode of derivation in Drosophila are shown 

 diagrammatically. Two germ cells, one from the female with the chro- 

 mosomes in outline, and the other from the male with the chromosomes 

 in full black, unite to form the female zygote shown in the middle of the 

 figure. The combinations of maternal and paternal chromosomes which 



