Discussion 209 



on the following terms. One could describe as a "sexual system" any- 

 one that involves more or less a total fusion of two genomes ; with the 

 subdivisions "eusexual" for unadulterated sexual reproduction, and 

 *'parasexual" for cases of less complete orthodoxy. "Transduction", 

 on the other hand, is a system in which only part of the genome from a 

 donor cell goes to a recipient. Under the term "transduction" Prof. 

 Lederberg also includes transformation, but since I have no vested 

 interest either in transformation or in transduction I would not like to 

 go further! 



Hayes: In a recent paper in conjunction with Drs. Wollman and Jacob 

 (Wollman, Jacob and Hayes 1956, loc. cit.) we have referred to these 

 bacterial systems involving partial zygotes as " merozygotic " systems; 

 but I was very careful to refer to them today as "parasexual" ones, as I 

 thought this would please Dr. Pontecorvo! 



Pontecorvo: That is very gratifying, but we have agreed with Prof. 

 Lederberg that it is not legitimate to call them "parasexual". 



