Publication

2005-08

English

http://archimer.ifremer.fr/doc/2005/publication-632.pdf (0.35 Mo)

2005 Publisher: Springer-Verlag New York

Mccombie Helen¹, Ledu Christophe¹, Phelipot Pascal¹, Lapegue Sylvie¹, Boudry Pierre¹, Gerard Andre²

1 : Inst Francais Rech Exploitat Mer, Lab Genet & Pathol, F-17390 La Tremblade, France.
2 : IFREMER, Ctr Nantes, F-44311 Nantes, France.

Marine Biotechnology (1436-2228) (Springer), 2005-08 , Vol. 7 , N. 4 , P. 318-330

7

Aquaculture, Biology

Oyster breeding, Gynogenesis, Polar body, Cytochalasin B, Polyploidy, Crassostrea gigas

We present a new method to produce tetraploid Crassostrea gigas by cytochalasin B inhibition of polar body 2 expulsion in diploid females crossed with tetraploid males. This offers a means of direct introgression of genetic characters from selected diploid to tetraploid lines, avoiding a triploid step. Offspring larval ploidy shifted over time and depended on size, with tetraploids more frequent among the smaller larvae and triploids among the large. Viable tetraploids were found at 4 and 6 months, indicating the technique was successful. The possibility that gynogenesis occurred was tested by microsatellite analysis to confirm the presence of paternally inherited alleles. These were present in all animals of the 2n x 4n + CB (female first) cross. However, a 4n x 2n + CB cross produced triploids, including some gynogens. Our method illustrates for the first time that diploid C. gigas eggs, if selected for large size, can give viable tetraploid offspring.