Mice that have a foreign gene introduced into their cells.
mice that have had a human gene (like APP) inserted into their chromosomes. Mice carrying the mutated human APP gene often develop plaques in their brains as they age.
These mice can be made by microinjection of DNA into the pronucleus of fertilized eggs, with the DNA integrating at random. They are useful for studying gene expression, overexpression, and rescue of the mutant phenotype.
these are mice that are used in research into various diseases and have been genetically engineered to carry a specific gene from another animal, injected into the fertilised ovum during gestation; there is quite a high failure rate though as this process is very difficult. Animals used for TSE research are given the PrP gene of another animal so that they will produce that animal's PrP protein instead of their own.
mice that receive injections of foreign genes during the embryonic stage of development. Their cells then follow the "instructions" of the foreign genes, resulting in the development of a certain trait or characteristic. Transgenic mice can serve as an animal model of a certain disease, telling researchers how genes work in specific cells.
These are mice carrying a specific gene from another animal. There may be more than one copy of the gene (for instance, in many transgenic mice containing the human PrP gene there may be over 20 copies) and may actually replace the gene that is there normally. The gene is unlikely to be at the same site as the normal gene in the animal chromosome. To insert the gene requires the DNA to be inserted into the fertilised ovum of the animal and hence is very difficult indeed, with many failures.
