116 GENETICS IN RELATION TO AGRICULTURE 



and in separating tend to break apart at places, and in reuniting exchange 

 chromatin material. Morgan has taken these two ideas and applied 

 them to the results of the Drosophila investigations. The twisting of the 



0.0 



1.1 



L4 



M 



12.6 

 14.6 

 16.7 



19.5 



23.7 

 26.5 



33.0 



36.1 



38.0 



43.0 



55.1 

 57.0 

 69.5 



Yellow. Spot 



Whit*. Cherry. Eosin 



Abnormal 



Bifid 



Lethal II 

 Lethal ib 



Club 

 Lethal Ilia 



Lethal sa 

 Lethal III 



Vermilion 



Miniature 

 Furrowed 



Sable 



Rudimentary 



Bar 



Fused 



o.o 



66.2 Lethal 



16.6 



Streak 



0.0 Sepia 



Dacha 



25.0 



34.7 Black 

 35.0 * Jaunty 



40.0 



52.0 



60.4 



84.1 



90.0 

 91.9 



Purple 



Vestigial 



Curved 



40.0 



65.0 



Bent 

 Eyeless 



Pink, Peach 



Kidney 



Ebony, Sooty 



Arc 



Speck 

 Morula 



73.0 Beaded 



85.0 Rough 



Fio. 54. Plotted relations of factors in Drosophila ampelophila. 



chromosomes in synapsis is held to be the physical evidence of the known 

 interchange of factors between chromosomes which takes place in crossing- 

 over. Moreover, if the factors are the individual elements of the chro- 



