VARIATION AND INHERITANCE 



40; 



Q Q Q Q Q 



Thiamin 



^ 



Complete 

 medium 



Ribo- 

 flavin 



Pyri- 

 doxin 



Panto- Niacin 

 thenif 

 acid 



p-Amino- 



benzoic 



acid 



Inositol Choline 



Folic 

 acid 



I © 



Nucleic 

 acid 



I 



Minimal 

 control 



Fig. 80. Tests of mutant on individual vitamins or growth factors. Growth only on 

 pantothenic acid indicates a single deficiency for this vitamin. (Courtesy of Beadle, 

 Am. Scientist 34: 39, 1946, and Science in Progress, 1947. Published by permission 

 of the Society of the Sigma Xi.) 



o 



I 

 f 



Fruiting 



D 



O 



QQOOQOQO 



Uhu) Mb* iHi iki iSS 



|r jF I I p 



KJ kJ \J \J kJ 



With pantothenic oicid 



i } 1 I 1 1 1 1 



QOOOQOQQ 



Panfothenicless 



p 



¥ 



B 



Wild 

 t:ype 



Without pantothenic acid 

 Fig. 81. Scheme by which the inheritance of a mutant type is determined. The 1 to 

 1 ratio with regard to need for pantothenic acid indicates simple Mendelian inheritance. 

 (Courtesy of Beadle, Am. Scientist 34: 40, 1946, and Science in Progress, 1947. Pub- 

 lished by permission of the Society of the Sigma Xi.) 



