DNA Microinjection into the Egg, Clones Cells, Recombinant Plasmids, Genome, Transposons, DNA microinjection, Mendelian Manner

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	DNA Microinjection into the Egg - Transfer of individual cloned genes is generally achieved by inserting into a fertilized egg, a large number of copies of recombinant plasmid carrying the gene of interest, using the technique of DNA microinjection. The DNA is microinjected into a fertilized egg before the fusion of male and female nuclei.
The egg is first immobilized by applying mild suction to the large, blunt holding pipette and DNA is then injected through the sharp end of a narrow glass microneedle. Through recombination at the DNA level, the inserted gene may get integrated into the host genome and inherited in a Mendelian manner. Transgenic mice have been produced in many laboratories, utilizing this technique. The method has also been successfully utilized for production of transgenic chicken, cows, fish, pigs, rabbits and sheep. In Drosophila, the P elements (transposons) are used as vectors, so that a recombinant P element carrying the foreign gene is used for microinjection. Although the microinjected flies may not carry the inserted gene in all cells, some of their progeny may carry the gene in all the cells.