author's abstract of this paper issued 

 by the bibliographic service, august 5 



THE DIRECTION AND FREQUENCY OF MUTATION 



IN THE BAR-EYE SERIES OF MULTIPLE 



ALLELOMORPHS OF DROSOPHILA^ 



CHARLES ZELENY 



University of Illinois 



FIVE FIGURES 



CONTENTS 



I. Material and method 203 



II. Data 209 



III. Discussion and conclusions 219 



IV. Summary 232 



V. Bibliography 233 



I. MATERIAL AND METHOD 



1, Introduction 



Series of multiple allelomorphs are valuable in studies of the 

 nature of mutation, because the changes involve a single germinal 

 material. In Drosophila melanogaster Meig the bar series, full 

 to bar to ultra-bar, has an especially valuable combination of 

 characteristics for such a study: 1) The details of the origin of 

 the components are known; 2) the facet counts make possible 

 a quantitative evaluation of the components; 3) the heterozy- 

 gotes may be recognized; 4) the mutations are frequent enough to 

 furnish an adequate measure of rate; 5) the change from bar to 

 ultra-bar may be considered as an intensification of the first 

 change from full to bar; 6) both direct and reverse mutations 

 have been observed. 



^ Contribution from the Zoological Laboratory of the University of Illinois, 

 no. 188. 



203 



