Section 12 — Plasmatic Inheritance 



12.21. Genetic Recombination with Drosophila <j 



Virus. A. Ohanessian (Gif-Sur-Yvette, France). 



The hereditary virus of Drosophila (<J virus) 

 shows numerous genetic variations. Several 

 genetic factors which are described, are con- 

 troling aspects of the relationships between the ct 

 virus and its host. It has been possible to estimate 

 the mutation frequency of two of them. 



Genetic recombination has been demonstrated 

 with ct virus. The recombination takes place 



when Drosophila eggs are mixedly infected with 

 two genetically different viral particles. One 

 resulted from the infection of an oocyte in a 

 non stabilized female and the other is brought 

 by a spermatozoon of a stabilized male. 



Genetic recombination probably occurs at the 

 beginning of Drosophila ontogenesis. The re- 

 combinants are detected in the resulting adult fly. 

 In the course of these experiments some par- 

 tial heterozygous particles are found. They are 

 heterozygous for one of the viral genes only. This 

 phenomenon has been observed several times. 



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