28-2 



THE YEAST CELL 



present in a gene -product concentration in which only one was pre- 

 viously present. This condition does not influence vegetative multi- 

 plication to a pronounced degree, but acts as a relatively effective 

 spore lethal since spores produced by these diploids are poorly vi- 

 able. Presumably a specific concentration of the gene -product is 

 essential to spore viability. Once the concentration has been lowered 

 it is not easily reestablished. However, this occasionally occurs pro- 

 ducing viable spores. 



The hypothesis also serves to explain Sonneborn's results in anti- 

 genic variation in paramecia. Each antigen is the expression of a 

 specific (gene -product to gene) equilibrium. Removal of the antigen 



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PLASMA MSMBRANE^ SOBSTRATEvi. 



Klliri CAD /WVCAACkOAMC-^ 



PROTEIN 



GENE-PRODUCT 



RISOSENUCLEOPeoTEIN 



co^APLEX^poEN^Yrt£?) 



CYTOPLASM 



COENZYME 



SPECIFIC ENZYME: ACUNG ON SUBSTRATE 



NUCLEAR MEMBRANE 



NUCLEOPLASM 



UNlOlRECTIOf4AL ♦ASSEMBLY ^MNE'*' 

 SVNTUeS\S OF SEN^ -PRODUCT 



.jfCHRpMOGENE (^ KEYtD TO LOCUSj 

 C)CUS 



CHROWOSCVAE- 



ONE GENE 



A REGION IN WWICW CROSSING-OVER 

 RARELY OCCURS 



