26-35 



THE YEAST aLL 



Microcolony transplanted 

 to glucose slant 



Haplopkase microcolonies 

 of single tetrad on glucose 

 agar droplets 



f'\4 



Cells from smear immediately 

 transferred into galactose 

 pour-plate 



Cells from smear imr 

 mediately transfer- 

 red into melibiose 

 pour-plate 



w 



Inoculum from glucose slant, 

 after luxuriant growth, tested 

 directly for mating type, etc. 



Fig. 26-1 Diagram Describing the Procedure Adopted to Mini- 

 mize mutations in single spore cultures in testing fermentative 

 characteristics of a haplophase segregant . 



face to obtain luxuriant growth. Mature inoculum from the glucose 

 slant was subsequently tested for mating type specificity, and fer- 

 mentative and vitamin- synthesizing abilities. Simultaneous tests 

 for galactose and melibiose fermentation by colonies developing on 

 galactose and melibiose pour plates were conducted. 



The widespread disturbances in segregations of fermenter 

 phenotypes (shown in Tables 26-18 and 26-19) are noteworthy, since 

 the stocks to which CiA and 609 were mated had been carefully se- 

 lected for regfular segregations for the characters. In spite of the 

 extensive non-Mendelian ratios, the truly hybrid nature of the asci 

 analyzed is evident from the regular segregations of at least t^o 

 marker genes in each ascus. Further support derives from the 



