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| Registros recuperados: 25 | |
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| Mccombie, Helen; Ledu, Christophe; Phelipot, Pascal; Lapegue, Sylvie; Boudry, Pierre; Gerard, Andre. |
| 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,... |
| Tipo: Text |
Palavras-chave: Oyster breeding; Gynogenesis; Polar body; Cytochalasin B; Polyploidy; Crassostrea gigas. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-632.pdf |
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| Boudry, Pierre; Leitao, Alexandra; Mccombie, Helen; Thiriot-quievreux, Catherine. |
| Cytogenetic abnormalities arising both in mitosis and meiosis are known to be common in bivalves. Here we review result obtained from the observations of somatic aneuploidy in different populations of the commercially important Pacific oyster, Crassostrea gigas. The oysters studied were either (1) produced in IFREMER hatcheries between 1986 and 1999, (some of these were part of the EU funded programme GENEPHYS); or (2) collected from wild populations along the French Atlantic coast. Chromosome numbers were scored from 30 mitotic metaphases in gill tissue per individual studied. Aneuploid cells (2n - X) were observed in all the 13 populations studied. A highly significant negative correlation was observed between the level of aneuploidy and growth, i.e.... |
| Tipo: Text |
Palavras-chave: Growth; Genetic; Aneuploidy; Crassostrea gigas; Pacific oysters. |
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/2000/acte-3446.pdf |
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| Mccombie, Helen; Lapegue, Sylvie; Cornette, Florence; Ledu, Christophe; Boudry, Pierre. |
| Alterations of chromosome number have been observed in the somatic tissue of Crassostrea gigas diploids and artificial polyploids bred in this species. Tetraploid animals with lower chromosome counts in some or all of their somatic tissue are considered undesirable as parents either for commercial triploids (produced via a cross with diploids) or for tetraploid breeding because (1) they may confer the tendency to lose chromosomes and revert to lower ploidy levels to their offspring or (2) their offspring could have a lower ploidy directly because of potential links between somatic and gametic chromosome loss. The present study evaluated the phenomenon in bi-parental tetraploid families bred from parents of differing ploidy quality, including a... |
| Tipo: Text |
Palavras-chave: Tetraploid; Chromosome; Genetic; Crassostrea gigas; Oyster. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/2003/acte-3435.pdf |
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| Ledu, Christophe; Mccombie, Helen. |
| The effects of cytochalasin B on fertilization and ploidy in Crassostrea gigas were examined in a controlled experiment. This enabled us to better understand why variable ploidy results have been found with the retention of polar bodies in previous studies on bivalve mollusks, and what the interaction with fertilization may be. By looking at the early development of Crassostrea gigas embryos with sequential samples stained using Hoechst 33258, a fluorescent DNA-specific dye, we compared normal evolution of fertilized eggs with that obtained with cytochalasin B treatment. In treated eggs, embryos with both three and four pronuclei were found after the second meiotic division. When embryos had three pronuclei, these were identified as the female pronucleus... |
| Tipo: Text |
Palavras-chave: Crassostrea gigas; Fertilization; Cytochalasin B; Polar body; Polyploidy. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/2003/publication-2845.pdf |
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| Lapegue, Sylvie; Mccombie, Helen; Leitao, Alexandra; Bouilly, Karine; Sabatier, Sebastien; Heurtebise, Serge; Boudry, Pierre; Thiriot, Catherine; Gerard, Andre. |
| Divers travaux menés depuis 1984 montrent qu'il existe, chez l'huître creuse Crassostrea gigas, des cellules montrant un nombre anormal de chromosomes (2n = 19, 18 ou même 17 au lieu de 2n = 20). Le niveau d'aneuploïdie est déterminé par le décompte des chromosomes à partir de suspensions cellulaires de tissu branchial. Le pourcentage de cellules aneuploïdes est toujours significativement supérieur dans les "lots de queue", c'est-à-dire les huîtres présentant des croissances plus faibles, et peut atteindre plus de 30 %. Récemment, une étude réalisée au sein du programme européen « Genephys » a démontré que plus de 50 % de la variance pour la vitesse de croissance était liée au taux d'aneuploïdie. Cependant, de nombreux points concernant ce phénomène... |
| Tipo: Text |
Palavras-chave: Génétique; Chromosomes; Anomalies; Aneuploïdie; Atrazine; Huîtres creuses; Crassostrea gigas. |
| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/00199/31013/29417.pdf |
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| Lapegue, Sylvie; Mccombie, Helen; Leitao, Alexandra; Bouilly, Karine; Sabatier, Sebastien; Heurtebise, Serge; Boudry, Pierre; Thiriot Quievreux, Catherine; Gerard, Andre. |
| Divers travaux menés depuis 1984 montrent qu’il existe, chez l’huître creuse Crassostrea gigas, des cellules montrant un nombre anormal de chromosomes (2n = 19, 18 ou même 17 au lieu de 2n = 20). Le niveau d’aneuploïdie est déterminé par le décompte des chromosomes à partir de suspensions cellulaires de tissu branchial. Le pourcentage de cellules aneuploïdes est toujours significativement supérieur dans les "lots de queue", c'est-à-dire les huîtres présentant des croissances plus faibles, et peut atteindre plus de 30 %. Récemment, une étude réalisée au sein du programme européen « Genephys » a démontré que plus de 50 % de la variance pour la vitesse de croissance était liée au taux d’aneuploïdie. Cependant, de nombreux points concernant ce phénomène... |
| Tipo: Text |
Palavras-chave: Génétique; Chromosomes; Aneuploïdie; Huîtres creuses; Crassostrea gigas. |
| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/00043/15474/12853.pdf |
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| Bouilly, Karine; Mccombie, Helen; Leitao, Alexandra; Lapegue, Sylvie. |
| Divers travaux menés depuis 1984 montrent qu’il existe, chez l’huître creuse Crassostrea gigas, des cellules montrant un nombre anormal de chromosomes (2n = 19, 18 ou même 17 au lieu de 2n = 20). Le niveau d’aneuploïdie est déterminé par le décompte des chromosomes à partir de suspensions cellulaires de tissu branchial. Le pourcentage de cellules aneuploïdes est toujours significativement supérieur dans les "lots de queue", c'est-à-dire les huîtres présentant des croissances plus faibles, et peut atteindre plus de 30 %. Cette corrélation négative entre l’aneuploïdie somatique et le taux de croissance a été décrite à de nombreuses reprises (Thiriot-Quiévreux et al., 1988, 1992 ; Leitão et al., 2001a ; Zouros et al., 1996). Bien que les causes... |
| Tipo: Text |
Palavras-chave: Génétique; Chromosomes; Aneuploïdie; Huîtres creuses; Crassostrea gigas. |
| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/00044/15475/12854.pdf |
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| Lapegue, Sylvie; Mccombie, Helen; Leitao, Alexandra; Heurtebise, Serge; Boudry, Pierre; Thiriot Quievreux, Catherine; Gerard, Andre. |
| Divers travaux menés depuis 1984 montrent qu’il existe, chez l’huître creuse Crassostrea gigas, des cellules montrant un nombre anormal de chromosomes (2n = 19, 18 ou même 17 au lieu de 2n = 20). Le niveau d’aneuploïdie est déterminé par le décompte des chromosomes à partir de suspensions cellulaires de tissu branchial. Le pourcentage de cellules aneuploïdes est toujours significativement supérieur dans les "lots de queue", c'est-à-dire les huîtres présentant des croissances plus faibles, et peut atteindre plus de 30 %. Récemment, une étude réalisée au sein du programme européen « Genephys » a démontré que plus de 50 % de la variance pour la vitesse de croissance était liée au taux d’aneuploïdie. Cependant, de nombreux points concernant ce phénomène... |
| Tipo: Text |
Palavras-chave: Génétique; Chromosomes; Aneuploïdie; Huîtres creuses; Crassostrea gigas. |
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/00043/15473/12852.pdf |
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| Boudry, Pierre; Heurtebise, Serge; Lapegue, Sylvie; Lam, Katherine; Mccombie, Helen; Leitao, Alexandra; Gerard, Andre. |
| L'étude de la variabilité génétique de l'huître creuse Crassostrea gigas est un point essentiel dans la mise en place de programmes de gestion des ressources génétiques et de sélection chez cette espèce. C. gigas, originaire du Japon, a été introduite dans de nombreuses régions du monde et représente aujourd'hui plus de 95 'ro de la production mondiale d'huîtres. Introduite en France au début des années 1970 pour remplacer l'huître portugaise Crassostrea angulata, c'est aujourd'hui une ressource de première importance pour notre région. Malgré la maîtrise du cycle de reproduction de l'espèce et son importance commerciale, elle n'a pas été génétiquement améliorée et on peut donc considérer les stocks comme « sauvages» ou « non domestiqués ». De plus, la... |
| Tipo: Text |
Palavras-chave: Génétique; Huîtres creuses; Crassostrea gigas; Crassostrea gasar; Variabilité génétique. |
| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/00199/31008/29411.pdf |
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| Lapegue, Sylvie; Thiriot Quievreux, Catherine; Mccombie, Helen; Heurtebise, Serge; Boudry, Pierre; Robert, Stephane; Soletchnik, Patrick; Goulletquer, Philippe; Gerard, Andre. |
| Divers travaux, menés depuis 1984, montrent qu'il existe, chez l'huître creuse Crassotrea gigas, des cellules montrant un nombre anormal de chromosomes (2n = 19, 18 ou même 17 au lieu de 2n = 20). Le niveau d'aneuploïdie est déterminé par le décompte des chromosomes à partir de suspensions cellulaires de tissu branchial. Le pourcentage de cellules aneuploïdes est toujours significativement supérieur dans les "lots de queue", c'est-à-dire les huîtres présentant des croissances plus faibles, et peut atteindre plus de 30 %. Récemment, une étude réalisée au sein du programme européen « Genephys » a démontré que plus de 50 % de la variance pour la vitesse de croissance était liée au taux d'aneuploïdie. Le but de l'expérimentation menée en 1999 est de faire un... |
| Tipo: Text |
Palavras-chave: Génétique; Aneuploïdie; Génétique des populations; Biochimie; Marennes-Oléron; Huître creuse; Crassostrea gigas. |
| Ano: 1999 |
URL: http://archimer.ifremer.fr/doc/00044/15522/12909.pdf |
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| Boudry, Pierre; Degremont, Lionel; Taris, Nicolas; Mccombie, Helen; Haffray, Pierrick; Ernande, Bruno. |
| The most significant genetic improvement for production of Pacific oyster (Crassastrea gigas) has been obtained through the breeding of triploids, especially since the development of tetraploids. Quantitative genetics studies suggest that significant gains, for disease resistance or for other traits of aquacultural interest, could be obtained using this approach. However, the limited extent of hatchery-propagation (versus natural recruitment) and/or various technical difficulties and biological characteristics of the species have slowed the development of selective breeding programs. Recently, in the USA, Australia and New Zealand, family-based selective breeding programs have been initiated to improve growth and yield. In Europe, where both natural and... |
| Tipo: Text |
Palavras-chave: Microsatellites; Quantitative genetic; Genetic variability; Crassostrea gigas; Oysters. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/2004/publication-2861.pdf |
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| Boudry, Pierre; Degremont, Lionel; Taris, Nicolas; Mccombie, Helen; Haffray, Pierrick; Ernande, Bruno. |
| To date, the most significant genetic improvement for the production of Pacific oyster (Crassostrea gigas) has been obtained through the breeding of triploids, especially since the development of tetraploids. Quantitative genetics studies suggest that significant gains, for disease resistance or for other traits of aquacultural interest, could be obtained in diploids using this approach. However, the limited extent of hatchery-propagation (versus natural recruitment) and/or various technical difficulties and biological characteristics of the species have retarded the development of selective breeding programs. Recently, in the U.S.A., Australia and New Zealand, countries where hatcheries are a major source of C. gigas juveniles, family-based selective... |
| Tipo: Text |
Palavras-chave: Microsatellite markers; Selective breeding; Genetic; Genetic variability; Crassostrea gigas; Pacific oysters. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/2004/acte-3449.pdf |
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| Cannuel, Rozenn; Beninger, Peter G.; Mccombie, Helen; Boudry, Pierre. |
| Study of gill development in bivalve larvae and postlarvae provides information on the evolution of this organ and feeding mechanisms of early stages. Scanning electron microscopy was used to document the development of the filibranch homorhabdic gill in hatchery-reared larval, postlarval, and juvenile Mytilus edulis. Four key stages were identified during gill development: (1) transfer of the particle collection function from velum to gill at metamorphosis, with subsequent elongation of the gill filaments to form a gill basket, with complete frontal ciliation; (2) reflection of the inner demibranchs, and transition to a V-shaped gill; (3) delayed development of the outer demibranchs, occuring simultaneously along the gill axis, with transition to the... |
| Tipo: Text |
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| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6935.pdf |
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| Bouilly, Karine; Leitao, Alexandra; Mccombie, Helen; Chaves, R.; Guedes Pinto, H; Boudry, Pierre; Lapegue, Sylvie. |
| In the Pacific oyster, Crassostrea gigas hypodiploid aneuploid cells with 2n=19, 18 or 17 chromosomes have regularly been reported. There is a negative correlation between somatic aneuploidy and growth rate in oysters (Leitão et al., 2001a) as well as evidence for a genetic basis (Leitão et al., 2001b). Furthermore, non-random chromosome loss has been demonstrated in aneuploid karyotypes of C. gigas using the G-banding technique (Leitão et al., 2001c). This poster summarises different studies used to investigate the effects of the herbicide atrazine on the level of aneuploidy in this species |
| Tipo: Text |
Palavras-chave: Genetic; Aneuploidy; Toxicology; Impact; Atrazine; Crassostrea gigas; Pacific oysters. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/2004/acte-3489.pdf |
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| Bouilly, Karine; Leitao, Alexandra; Mccombie, Helen; Miramand, Pierre; Lapegue, Sylvie. |
| Aneuploidy is the alteration of the normal diploid chromosome number. In the Pacifie oyster, Crassastrea gigas, hypodiploid cells have regularly been reported as have a negative correlation between this phenomenon and growth and evidence for a genetic basis. We previously demonstrated a positive relationship between a pollutant, atrazine, and aneuploidy in Crassastrea gigas adults and juveniles. To evaluate the persistence of this impact, the present study focused on a sample of the same juveniles previously exposed to different atrazine treatments (0.0 1 mg/l which represents a peak value found in a polluted environment and 0.1 mg/l) for three and a half months. Then, we evaluated them for aneuploidy after another two and a half months in non polluted... |
| Tipo: Text |
Palavras-chave: Cadmium; Atrazine; Pollutant; Pacific oyster; Aneuploidy. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/2003/acte-2852.pdf |
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| Boudry, Pierre; Collet, B; Mccombie, Helen; Ernande, Bruno; Morand, B; Heurtebise, Serge; Gerard, Andre. |
| In order to study individual growth variability and its relationship with survival in juvenile Crassostrea gigas, parental oysters were sampled at four sites located along the French Atlantic coast and bred under controlled hatchery conditions. Four groups of larvae were obtained by crossing five males and five females from each of the four sites, and a fifth group by crossing these 20 males and 20 females together in a pool. Larvae were reared under conditions allowing the maintenance of a maximum variability of size and gave five experimental groups. Oysters were individually monitored for growth and survival from 3 to 10 months after fertilization. The individual growth performances were relatively stable over time and no noticeable compensation for... |
| Tipo: Text |
Palavras-chave: Survival; Oysters; Growth; Crassostrea gigas; Aquaculture. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/2003/publication-467.pdf |
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| Huvet, Arnaud; Fabioux, Caroline; Mccombie, Helen; Lapegue, Sylvie; Boudry, Pierre. |
| The marine environment is of special interest for studying hybridization between closely related taxa because of the high dispersal potential of planktonic larvae, such as those of most bivalve species. The oysters Crassostrea angulata and C. gigas are known to be very close genetically and entirely inter-fertile under controlled conditions. However, hybridization in the wild had not been investigated, mainly due to the lack of nuclear diagnostic markers. In the present paper, we first estimated genetic differentiation between these 2 closely related taxa using 8 microsatellite markers. Interestingly, 5 markers displayed significant differences of allele size between taxa. The subsequent sequencing of alleles of one of these microsatellites showed several... |
| Tipo: Text |
Palavras-chave: Allele size; Microsatellites; Genetic differentiation; Hybridization; Crassostrea gigas; Crassostrea angulata. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/2004/publication-3355.pdf |
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| Registros recuperados: 25 | |
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