1. The first drug manufactured using recombinant DNA
technology was insulin, which is produced in bacterial cells
(E. coli). Before 1982, people with type 1 diabetes mellitus
obtained the insulin that they injected daily from pancre-
ases removed from cattle in slaughterhouses. Cattle insulin
is so similar to the human peptide, differing in only 2 of its
51 amino acids, that most people with diabetes could use it.
However, about 1 in 20 patients is allergic to cow insulin
because of the slight chemical difference. Before
recombinant
DNA technology, the allergic patients had to use expensive
combinations of insulin from other animals or from human
cadavers.
Insulin is a peptide and is therefore straightforward
to mass-produce in bacteria. Some drugs, however, require
that sugars be attached to peptides or proteins, or that the
proteins fold in specific, intricate ways to function.

2. Transgenic non-human mammals can
express human
genes in their milk, including genes that
encode clotting
factors, clot busters, and the connective
tissue protein collagen. Human antibodies
produced in rabbit and cow milk, for
example, are used to treat cancers

3. Malaria remains one of Africa’s
deadliest diseases, killing nearly
half a million children under the
age of 5, and accounting for
approximately 95% of global
malaria cases and 96% of
deaths in 2021.
“Nearly every minute, a child
under 5 years old dies of
malaria,

4. A vaccine that protects against malaria is based on
altering a bacterium (Pantoea agglomerans) that
normally
inhabits the mosquito gut. Mosquitoes transmit
Plasmodium
falciparum, the parasite that causes malaria. The
bacteria are
given genes from E. coli bacteria that enable them
to produce proteins that tear apart the insect’s
intestines. Using recombinant bacteria is easier
than genetically modifying mosquitoes
to prevent malaria

5. Atlantic salmon that grow faster on
less food than unaltered
salmon, due to genes from Chinook
salmon and a gene from
an eel-like ocean pout, is an
example of a transgenic organism