Humulin and the Wonderful E. Coli

Before 1978 diabetics had a major problem. Insulin was hard to find, expensive, caused allergic reactions in some people, and was against some religions to use it at all. Before 1978 the only way to produce insulin was to grind up the pancreas of either a cow or a pig and extract the small amount of insulin. Since human, cow and pig insulin are slightly different some people exhibited allergic reactions to the "farm animal" insulin. In addition some lifestyles and religions prohibit the consumption of cattle (Hindus), pork (Jews and Muslims), or both (vegans and vegetarians). But in 1978 Genetech created a synthetic human insulin called Humulin. 

Humulin is not just similar to human insulin, it is human insulin. The only difference is that it is not made in a human body, it is made in an E. Coli cell culture. When most people hear E. Coli they think that is the evil bacteria that make you sick. Not true. You actually have millions and millions inside you right now that are helping your body with digestion and other functions, but people only seem to know E. Coli O157:H7 (the toxin producing strain). Genetech took some of the friendly strains of E. Coli and added a few genes, more specifically the genes that code for human insulin production and ones that code for the production of an antibiotic. Those E. Coli that successfully accepted the extra genes were able to survive, because of the antibiotic, while those that did not died. The gene carrying E. Coli continue to replicate and produce humulin. They have no idea why they are producing humulin but their genetic code tells them to so they do. 

This technology of introducing recombinant human DNA to E. Coli did not stop at humulin. Today E. Coli help produce our bodies natural blood thinners and thickeners (to prevent and encourage clotting), immune system boosters, growth hormones, and much more.