author's abstract op this paper issued 



BT the bibliographic service OCTOBER 8 



FLUCTUATIONS IN A RECESSIVE MENDELIAN 

 CHARACTER AND SELECTION^ 



ELMER ROBERTS 

 University of Illinois, Urbana, Illinois 



TWO PLATES AND THREE TEXT-FIGURES 



CONTENTS 



I. Introduction 157 



II. Material and methods 158 



1. Sources of error 160 



III. Experimental data 161 



1. Selected series A 161 



a. Effect of selection 161 



b. Control series B 163 



c. Effect of temperature 163 



2. 'Crossed-in-and-selected' series C 164 



a. Effect of selection 164 



b. Effect of ' crossing-in' 166 



c. Effect of temperature 168 



3. Form of wings 169 



IV. Summary of results 170 



V. Discussion 171 



1. Effect of selection 171 



2. Effect of ' crossing-in' 172 



VI. Literature cited 176 



Plates 178 



Tables 182 



I. INTRODUCTION 



During the past few years there has been much discussion 

 concerning the purity of the germ-plasm and the constancy of 

 MendeUan characters. Johannsen, De Vries, and others have 



^ Paper No. 7 from the Laboratory of Genetics, Department of Animal Hus- 

 bandry, University of Illinois. The writer wishes to acknowledge his indebted- 

 ness to Dr. J. A. Detlefsen, under whose direction the work was carried on, for 

 many valuable suggestions and criticisms. 



157 



the journal of EXPERIMENTAL EOQlOGY, VOL. 27, NO. 2 



