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 F-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 FI female the reduction divi- 



R 



F, 



FIG. 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 

 FI 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 



