36 IMPROVING THE APPLICATION OF NUCLEAR TRANSFER FOR PRODUCING NON-DOMESTIC FELIDS
Notice bibliographique
Résumé
One of the most remarkable aspects of somatic cell nuclear transfer (NT) is the possibility of avoiding extinction when there are few remaining animals of a specific felid population. Previously, we produced live male African Wildcat (AWC; Felis lybica) cloned kittens using inter-species nuclear transfer (Gomez et al. 2004 Cloning and Stem Cells 6, 217–228). The production of females is a primary objective of most breeding programs. Therefore, the purpose of the present study was to determine (1) if we could produce live female AWC cloned kittens at a proportion similar to that previously demonstrated with males, and (2) if our inter-species NT technique used to produce AWC is applicable to in vitro production of another non-domestic felid species. Specifically, we evaluated the in vivo developmental competence of NT embryos derived by fusion of Black footed cat (BFC, Felis nigripes) and AWC fibroblasts with domestic cat (DSH, Felis catus) cytoplasts, after transfer into domestic cat recipients. Fibroblast cell lines were established from skin biopsies of BFC (6-year-old), and AWC (12-year-old) adult females. After at least three passages, cells were serum-starved for 5 days and injected into the perivitelline space of enucleated domestic cat oocytes. Fusion of cell-cytoplast couplets was induced by applying a 3-s AC pre-pulse of 20 V, 1 MHz, followed by two 30-µs DC pulses of 240 V/mm. Fused couplets were activated 2 to 3 h after fusion by exposure to two 60 µsec DC pulses of 120 V/mm, followed by 4 h incubation with 10 µg/mL cycloheximide and 5 µg/mL cytochalasin B. Reconstructed BFC (n = 16) and AWC (n = 536) NT Day 1 embryos were transferred by laparoscopy into the oviducts of 1 and 12 gonadotrophin-treated DSH recipients, respectively, on Day 1 after induced ovulation. Pregnancy was assessed by ultrasonography on Day 22. One cat (100%) receiving BFC NT embryos and 5 (41.6%) cats receiving AWC NT embryos became pregnant. Twenty-three AWC cloned embryos implanted and 11 kittens were born. Three BFC NT embryos implanted and the pregnancy is currently ongoing. AWC cloned kittens were phenotypically and genetically identical to their somatic cell donor. Their clonal identity was assessed by multiplex PCR amplification of 20 microsatellite markers, including seven markers that are known to be on the X chromosome. In summary, these results indicate that female AWC cloned kittens can be produced and BFC pregnancy can be established in domestic cat recipients. The embryo implantation rate and viability of AWC female cloned embryos was higher than that observed after the transfer of AWC male cloned embryos. The difference may be due to improvements in the NT procedure, rather than to differences in the sex of the cell lines. Table 1. Implantation rate and fetal survival to term of AWC and BFC NT embryos in pregnant domestic cat recipients
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,001 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».