Autotetraploid Pacific oysters (Crassostrea gigas) obtained using normal diploid eggs: induction and impact on cytogenetic stability

• Published in: Genome
• Main Authors: Benabdelmouna, Abdellah, Ledu, Christophe
• Other Authors: Laboratoire de Génétique et Pathologie des Mollusques Marins (LGPMM), Santé, Génétique et Microbiologie des Mollusques (SGMM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2015
• Subjects: [SDV]Life Sciences [q-bio]; Pacific; Crassostrea gigas; Pacific oyster
• Online Access: https://hal.science/hal-04200621; https://doi.org/10.1139/gen-2015-0014

We describe two methods of producing viable and fertile autotetraploid Pacific oyster (Crassostrea gigas Thunberg) based on the use of normal-sized oocytes produced by normal diploid females. Our methods showed that the oocyte size is not a limiting factor for the success of the induction to autotetraploidy. These methods offer means of direct introgression of genetic progress from elite diploid lines to tetraploids used as broodstock, avoiding atriploid step with the risk of transferring undesirable traits from highly fecund triploids. High variability in the level of cytogenetic stability was found among the different tetraploid oysters tested showing that induction method has an important impact on the long-term cytogenetic stability of the tetraploids. It appears that induction method based on the use of triploid females induces a greater cytogenetic instability among tetraploids so obtained, and this compared to tetraploids originating from the two methods described in our present study. As the aneuploidies and reversions observed in tetraploids can have serious consequences for the sustainability of tetraploid broodstock itself as well as their triploid offspring, the two tetraploid induction methods described in the present work offer means to produce tetraploids with optimal cytogenetic, genetic and zootechnical performances Nous décrivons deux nouvelles méthodes de production d’huîtres du Pacific (Crassostrea gigas Thuneberg) autotétraploïdes basées sur l’utilisation d’ovocytes de taille normale issus de femelles diploïdes normales montrant ainsi que la taille des ovocytes n’est pas un facteur limitant pour la réussite de l’induction à la tétraploïdie. Ces méthodes permettent l’amélioration génétique des souches tétraploïdes en y transférant le progrès génétique réalisédans le compartiment diploïde et ceci tout en évitant le risque de transférer les caractères indésirables potentiellement transmis par les femelles triploïdes hyper fécondes. Des différences très nettes concernant la stabilité ...