To treat heritable emphysema, normal α 1-antitrypsin
gene is cloned into a vector and
transfected to sheep cells together with sheep promoter specific to mammary cells.
The recombinant cells are injected into the nucleus of a sheep zygote with a micropipette.
The zygote is then transferred to the uterus of a surrogate ewe for development.
When the transgenic sheep matures,
it will produce milk containing functional human α 1-antitrypsin.