How Are Transgenic Animals Produced?

Original paragraph

Since the discovery of the molecular structure of DNA by Watson and Crick in 1953, molecular biology research has gained momentum. Molecular biology technology combines techniques and expertise from biochemistry, genetics, cell biology, developmental biology, and microbiology.

Scientists can now produce transgenic animals because, since Watson and Crick’s discovery, there have been breakthroughs in:

The insertion of a foreign gene (transgene) into an animal is successful only if the gene is inherited by offspring.

The success rate for transgenesis is very low and successful transgenic animals need to be cloned or mated.

• recombinant DNA (artificially-produced DNA)
• genetic cloning
• analysis of gene expression (the process by which a gene gives rise to a protein)
• genomic mapping

The underlying principle in the production of transgenic animals is the introduction of a foreign gene or genes into an animal (the inserted genes are called transgenes). The foreign genes “must be transmitted through the germ line, so that every cell, including germ cells, of the animal contain the same modified genetic material.” (Germ cells are cells whose function is to transmit genes to an organism’s offspring.)

To date, there are three basic methods of producing transgenic animals:

• DNA microinjection
• Retrovirus-mediated gene transfer
• Embryonic stem cell-mediated gene transfer

Key ideas:

• Scientists now can produce transgenic animals because of several breakthroughs in recombinant DNA, genetic cloning, analysis of gene expression and genomic mapping
• The principle of the production of transgenic animals is the introduction of a foreign gene into an animal
• There are three methods of producing transgenic animals which are DNA microinjection, retrovirus-mediated gene transfer and embryonic stem cell-mediated gene transfer

Source 
Margawati, Endang T. "Transgenic Animals: Their Benefits To Human Welfare." Actionbioscience. N.p., n.d. Web. 06 Oct. 2014. <http://www.actionbioscience.org/biotechnology/margawati.html>.


Paraphrasing

Transgenic animals are able to be produced by scientists today because of several breakthroughs in recombinant DNA or artificially-produced DNA, genetic cloning, analysis of gene expression and genomic mapping.

The production of transgenic animals is basically the introduction of a foreign gene from another species into an animal. So far, there are three methods of producing transgenic animals which are DNA microinjection, retrovirus-mediated gene transfer and embryonic stem cell-mediated transfer.