GENETICS IN RELATION TO AGRICULTURE 



autosomes. A vestigial white female produces eggs all of which contain 

 an A'-chromosome bearing the factor w and an autosome bearing the fac- 

 tor v. Half the sperms, on the other hand, contain an ^-chromosome 

 bearing the factor W and an autosome bearing the factor V, and half con- 

 tain a }'-chromosome and an autosome bearing the factor V. Conse- 

 quently when the sperm cells which contain X-chromosomes fertilize 

 the eggs, Fi females of the genetic constitution Vv(WX)(wX) will be 



sperms 



Ot 



Long Red 



Long Red? 



Long White ? 



Long Red ? 



Long Red o* 



Long White cf 



Long Red c? 



yHyJynM J 



Long White 



Fio. 42. Fi gametes and Fj zygotes from the cross, vestigial white female X long red 

 male. Factor symbols: r = vestigial, V = long, w = white, W = red. 



produced. Phenotypically they will be long red. When the sperm 

 cells which contain } r -chromosomes fertilize the same kind of eggs the 

 Fi males which result will be of the genetic constitution Vv(wX)Y. 

 Phenotypically they will be long white. The reduction divisions in the 

 FI female will result in the production of four kinds of eggs as 

 shown diagrammatically in the figure. They will be of the genetic 

 constitutions: 



V(WX) v(WX) V(wX) v(wX). 



Similarly four kinds of sperm cells will be produced by the FI male 

 and they will be of the genetic constitutions: 



V(wX) v(wX) VY vY. 



