Generation of genetically modified mice using CRISPR/Cas9 system requires the delivery of CRISPR reagents into the genome. Some scientists use pronuclear microinjection of CRISPR reagents while the others use cytoplasmic microinjection. What are the determinant factors for using each of them?
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The most popular and more traditional method for generating transgenic mice is pronuclear microinjection where transgenic DNA is injected into the pronucleus of a fertilized egg. In cytoplasmic injection, the transgenic DNA is injected into the cytoplasm instead.
1. Cytoplasmic microinjection is technically easier to achieve than pronuclear injection.
2. Cytoplasmic microinjection has higher survival rates of zygotes, good rates of development and birth rates and high efficiency in mutant generation even in difficult to use inbred strains, compared to pronuclear injection.