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 
00 SAd SC ye 
PG dG die Yi 
Fic. 31.—Diagram showing consequences of independent segregation of chromosomes in 
Drosophila ampelophila. 
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 
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