The Paternal-Sex-Ratio Chromosome of Nasonia

1991 ◽  
Vol 137 (3) ◽  
pp. 392-402 ◽  
Author(s):  
John H. Werren
Keyword(s):  
Chromosoma ◽  
2005 ◽  
Vol 114 (6) ◽  
pp. 410-419 ◽  
Author(s):  
Joke J. F. A. van Vugt ◽  
Silvester de Nooijer ◽  
Richard Stouthamer ◽  
Hans de Jong

2009 ◽  
Vol 276 (1676) ◽  
pp. 4149-4154 ◽  
Author(s):  
Joke J. F. A. Van Vugt ◽  
Hans de Jong ◽  
Richard Stouthamer

This study uses molecular and cytogenetic methods to determine the origin of a B chromosome in some males of the wasp Trichogramma kaykai . This so-called paternal sex ratio (PSR) chromosome transmits only through sperm and shortly after fertilization triggers degeneration of the paternal genome, while keeping itself intact. The resulting embryos develop into haploid B-chromosome-carrying males. Another PSR chromosome with a very similar mode of action is found in the distantly related wasp Nasonia vitripennis and its origin was traced by transposon similarity to the genus Trichomalopsis , which is closely related to Nasonia . To determine whether both PSR chromosomes have a similar origin we aimed to reveal the origin of the Trichogramma PSR chromosome. Using fluorescent in situ hybridization, we discovered a major satellite repeat on the PSR chromosome, the 45S ribosomal DNA. Analysis of the internal transcribed spacer 2 (ITS2) of this repeat showed the presence of multiple ITS2 sequences on the PSR chromosome resembling either the ITS2 of T. oleae or of T. kaykai . We therefore conclude that the Trichogramma PSR chromosome originates from T. oleae or a T. oleae -like species. Our results are consistent with different origins for the PSR chromosomes in Trichogramma and Nasonia .


Author(s):  
Hans de Jong ◽  
Richard Stouthamer ◽  
Joke J.F.A. van Vugt

Genome ◽  
1993 ◽  
Vol 36 (1) ◽  
pp. 157-161 ◽  
Author(s):  
Kent M. Reed

Paternal sex ratio (PSR) is a B chromosome found in the parasitic wasp Nasonia vitripennis. PSR has a unique etiology in that it destroys the paternal chromosomes of fertilized eggs, resulting in the production of all male families. This study examined structural aspects of PSR including size, C-banding, and silver staining. PSR was found to constitute approximately 5.7% of the genome of carrier males. C-banding confirmed the heterochromatic nature of PSR and the data suggest that PSR remains primarily condensed throughout the cell cycle. Examination of prometaphase spermatocytes revealed a secondary constriction on PSR. The constriction, however, did not stain positive for nucleolus organizer activity. During mitosis, PSR and the pericentromeric regions of the A chromosomes displayed a temporal pattern of silver staining, involving dense precipitation of silver prior to metaphase. This reaction is indicative of a protein complex specific to the heterochromatin of these regions. The implications of these findings to the origin of PSR are discussed.Key words: Nasonia vitripennis, paternal sex ratio, B chromosome, nucleolus organizer region, heterochromatin.


Heredity ◽  
1993 ◽  
Vol 70 (4) ◽  
pp. 437-443 ◽  
Author(s):  
Leo W Beukeboom ◽  
John H Werren
Keyword(s):  

Sign in / Sign up

Export Citation Format

Share Document