76 GENETICS IN RELATION TO AGRICULTURE 
(WX)(wX), and it will be red-eyed because red is dominant over white. 
When such an egg is fertilized by a Y-bearing sperm a male is produced of the 
genetic constitution (WX)Y and it is red-eyed because the X-chromosome 
of the egg-cell carries the factor W. In the F; female the reduction divi- 
Fic. 36.—Inheritance of white eye color in Drosophila. White-eyed female mated with 
red-eyed male. Dotted lines indicate history of chromosomes of female; solid and gray 
lines, of the male. (Adapted from Morgan.) 
sions separate the X-chromosome bearing the factor for red eyes from 
the X-chromosome bearing the factor for white eyes. Consequently the 
F, female produces two types of eggs, (WX) and (wX). In the F; male 
the sperm cells similarly produced will be of two kinds (WX) and Y. 
As shown in the diagram there are four possible combinations of such 
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