Answer: They are used to produce human proteins in milk, organs for xenotransplantation, and better meat and milk.
Transgenic pigs:
- Pigs carrying human genes (that prevent rejection) are being developed so that their organs such as heart and kidney can be transplanted into humans (xenotransplantation).
- Transgenic pigs with genes for growth hormone or improved fat metabolism give leaner meat with faster growth; pigs with a gene for omega-3 fatty acids give healthier meat.
- Used as models to study human diseases and to produce human proteins (e.g. human haemoglobin) for therapy.
Transgenic cattle:
- Used as “bioreactors” to secrete valuable human proteins in their milk, e.g. the transgenic cow Rosie (1997) produced milk enriched with human α-lactalbumin, more nutritious for human babies.
- Transgenic cattle can produce pharmaceutical proteins such as lactoferrin, clotting factors and antibodies in milk, which are easily purified.
- Genes for higher milk yield, faster growth and disease resistance (e.g. against mastitis) improve dairy and meat production.
