Transgenic and genetically modified animals are being
increasingly used in the study of diseases and for safety
assessments of new compounds. They are a powerful tool for
developing a more detailed understanding of the role specific
genes play in biological pathways. The Federation of European
Laboratory Animal Associations defines a transgenic animal as an
animal in which there has been a deliberate modification of its
genome. The first transgenic mouse was created in 1974 by Rudolf
Jaenisch, a biologist from MIT. He created this transgenic mouse
through micro-injection of Simian virus 40 to explanted mouse
blastocysts and early embryonic exposure to retrovirus. The
technology to create transgenic animals broke new ground in the
scientific community and enabled scientists to seek new ways of
treating diseases and developing new drugs. The ability to
introduce new genetic information into the germ line of complex
organisms has completely changed and enhanced the study of all
aspects of biologic processes. The