New traits can be introduced into animals. Here's how it works for animals engineered to produce a human pharmaceutical.
1. Generation of the DNA Construct
A. Milk Protein Promoter DNA: allows for expression only in goat mammary glands.
B. Therapeutic Protein Gene: encodes a protein known to treat disease in people.
C. Terminator Sequence: assures that only the gene of interest is controlled by A.
D. Other DNA Sequences: helps with the introduction of the new combination DNA strand.
2. The DNA construct is created by combining A, B, C and D.
3. This new DNA strand is then introduced by any of a number of methods into an animal cell, such as an egg, that is then used to produce a genetically engineered animal.
4. The first genetically engineered goat is produced.
5. The offspring of the first genetically engineered goats, referred to as production animals, are milked. The milk is transferred to a purification facility.
6. The drug to be used to treat human disease is purified from the goat's milk.