Many people don’t think of it as a milestone in biotechnology, but agriculture was one of the first. After all, agriculture involved using living organisms to make a product. Crops like potatoes and tomatoes were modified and bred over the years to evolve from poisonous plants to the nutritious foods eaten today. Wine, beer and bread production are other examples of biotechnology. Fermentation by bacteria or yeast is used to create these products.

Penicillin is a mold discovered in 1928, and is still used as an antibiotic. However, ordinary people had known for many years that a blue green mold that grew on bread was good for healing wounds. This too was an instance of biotechnology.

By the 1920′s, insulin was being biosynthesized to treat diabetes. Now, the human insulin gene is injected into plants , yeast, or E. coli cells, and they produce human insulin. Before, animals like cows or pigs were used.

Now plants can be genetically engineered to resist drought, or insects, or to produce a greater yield. Bacteria that are toxic to insect pests have been introduced into some crop plants, for example.

In the 21st century, gene therapy is being used more and more to treat disease. In gene therapy, normal genes are used to replace damaged genes. Embryonic stem cells have been shown to be promising as treatments for disease, but their use is controversial.

Cloning is another controversial example of a biotechnological milestone. When an organism is cloned, the nucleus of one cell is placed inside an egg cell. This egg cell is unfertilized, and its own nucleus has been taken out. The egg cell will then, it’s hoped, grow into an embryo that’s identical to the organism that donated the nucleus. In 1997 Dolly the sheep was cloned from another sheep. As an embryo, she was implanted into the womb of a sheep who was not genetically her mother. Though she died young for a sheep, Dolly was otherwise fairly normal, and had six babies of her own. Since Dolly, other large mammals have been cloned.