238 CELLS, TISSUES, AND ORGANISMS 



and multiple marked stocks will have to be employed before this con- 

 clusion can be accepted without reservation. It will then be of interest 

 to learn at what times of the life cycle and under what conditions syn- 

 gamy, karyogamy, and reduction divisions occur. Is the system com- 

 plicated by the existence of mating types or fertility factors? Does the 

 reduction in ploidy that leads to the appearance of parental segregants 

 and recombinants operate via a meiotic or a parasexual process? At 

 this writing, mating stocks with conveniently scorable genetic markers 

 are being synthesized, and we hope to provide the answers to these 

 questions in the near future. 



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