• Detailed characterization of the original gene intended for introduction into the animals should be provided.
  
  
• The natural protein and its functions should be described along with a description of its pattern of expression.
  
  
• Both the original vector sequence and the transgene construct should be extensively characterized by restriction maps and nucleotide sequences. 

    C. Characterization of the transgenic founder (F0) animal:

• The medical history of the animals which donate gametes or embryonic stem cells (donor) and foster or recipient animals should be well known.
  
  
• Animals should undergo detailed veterinary evaluations of health, including breed-related and specific tests for species related disease problems.

6-3.5 Importance of Transgenic Animals:

1. Targeted Production of Pharmaceutical Proteins: Transgenic animals are used for the production of valuable human enzymes, hormones, antibodies and growth factors. Transgenic animals (eg. larger mammals) as bioreactor (“Pharmaceutical pharming”) is  cost effective compared to cell culture methods as animals can supplement their body fluid with fresh nutrients, remove waste products, internally regulate the temperature and pH and resist pathogens on their own. The transgene products can be collected by targeting its expression in the secretory cells of the liver, lactating mammary gland and kidney. e.g. - Sheep secreting human Factor IX in milk used for the treatment of hemophilia B.
   
   
2. Models of Human Disease Processes: To study different human disease patterns and their mechanisms, different lower animals having evolutionary resemblance to human are used. Due to stringent regulatory and ethical issues, direct experiment on human is not possible. The phenotypic and regulatory parameters of a particular human disease may be evaluated in an animal model with relatively short generation time. By expressing human proteins in a transgenic animal, the regulation and activity can be studied. Also by creating a condition similar to human diseased condition (eg. diabetic mice), one can study various parameters and their interaction. Developing diverse transgenic phenotypes permits the innovative testing of diagnostics and therapeutic agents with a reduced population of experimental animals. Utilizing novel cell lines from transgenic organs can lead to huge reduction in the number of research animals required for the evaluation. It is possible to create a transgenic genome in which more than one transgene may interact or in which a transgene may interact with endogenous normal or mutated gene. e.g. - transgenic rodent model are developed for numerous human disease like cardiovascular disease, cancer, etc.