Term
| 1974 - Jaenisch and Mintz |
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Definition
| They found that when purified SV40 DNA was injected into the blastocoel cavity of mouse blastocysts, viral DNA sequences could be detected in somatic tissues of many of the resulting animals, this suggests taht they had integrated into the genome of embryonic cells. |
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Term
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Definition
| Discovered that Maloney minnie leukemia virus (a retrovirus) could be stably introduced into the germline by viral infection of preimplantation mouse embryos. |
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Term
| 1980 - Anderson et al., and Capecchi |
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Definition
| They reported taht microinjected DNA into fibroblast cells led to the stable incorporation and expression of the injected transgene. |
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Definition
| This was the first introduction of a cloned gene into mouse somatic tissues by pronuclear injection. |
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Term
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Definition
| DNA can be injected directly into the proculei of freshly ferilised mouse eggs. Immediately following fertilisation, the male and female pronuclei are visible under the microscope. DNA injections are usually made into the larger male pronucleus whilst the eff is being held in position using a suction pipette in a micromanipulation device. The injected DNA will integrate into the pronuclear DNA which will be incorporated into the zygote. The injected embryos are cultured in vitro until the morula stage and then implanted into the pseudo-pregnant female. Once the embryo has developed into a mouse pup if the foreign DNA has been successfully transferred into the mouse, then the pup will be heteroygous for the new DNA. |
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Term
| Advantage of pronuclear injection |
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Definition
| DNA to be inserted does not need to be contained within a vector. |
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Term
| Disadvantages of pronuclear injection |
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Definition
-Only be used to add genes and cannot be used to delete or alter genes.
-Randomness of insertion
-The expression of the transgene is not strictly inherited.
-Insertional mutagenesis
-Can occassionally result in a mosaic animal where the transgene is only present in a limited set of tissues and organs of the animal. |
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