Comparing the Birth Rates of Microinjected Hybrid Mouse Zygotes Transferred into Outbred and Hybrid Foster Mothers


Abstract: The purpose of this study was to compare the birth rates after transfers of microinjected hybrid mouse zygotes into hybrid CB6F1 (C57BL/6J X BALB/c) and outbred CD-1 foster mothers. One or two hours after microinjection of a \beta -actin-Gfp gene construct into the male pronucleus, hybrid mouse zygotes were transferred into CB6F1 and CD-1 foster mothers. In addition, non-microinjected hybrid zygotes were transferred into foster mothers of both strains. The overall data demonstrate that outbred CD-1 foster mothers are a better choice for transfer of microinjected hybrid mouse embryos, and there was a statistical difference between the transfers of microinjected zygotes into CB6F1 and CD-1 foster mothers (P<0.001). Furthermore, there was also a statistical difference when microinjected and non-microinjected hybrid mouse embryos were transferred into CB6F1 foster mothers (P<0.05). However, the same difference was not observed when CD-1 foster mothers were used for transfer. When control groups are compared, data suggest that although there was no difference in terms of birth rate, more pups were obtained from transfer of non-microinjected embryos into CD-1 foster mothers. Thus, we suggest that CD-1 female mice are more suitable foster mothers than CB6F1 female mice,not only for microinjected hybrid mouse embryo transfer but also for non-microinjected hybrid mouse embryos.

Keywords: Microinjection, pronuclear stage, embryo transfer, hybrid, outbred

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