Many of our common crops, such as corn, canola, potatoes, tomatoes, squash, and soybeans, are genetically modified.
The majority of these crops were herbicide-resistant as well as insect-resistant, while the others may contain increased nutrients such as vitamins, produce yield earlier, or are able to survive weather extremes. Genetically modified tomatoes were introduced to the market in 1994, becoming the first commercially grown transgenic crop. They have longer shelf-life than the average tomatoes as they produces less of the substance that causes tomatoes to rot, so remains firm and fresh for a long time. In addition, transgenic corn is resistant to commercial herbicides such as glyphosate or glufosinate. It is also insect resistance by producing a poison which kills harmful insects.
Vitamin-enriched corn contains increased amount of vitamin A, vitamin B and vitamin C compared to the normal corn. Another example of GMO is squash. Genetically modified squash have resistance to the common squash viruses, namely watermelon mosaic virus, zucchini yellow mosaic virus and cucumber mosaic virus.
Other than crops, farm animals are also genetically modified to mature in a shorter time period to minimize expenses and increase profits for farmers, as well as to be resistant to certain diseases. For example, genetically-modified cow is resistant to bovine spongiform encephalopathy (mad cow disease). One of the examples of increased growth rate in genetically modified animals is fishes including salmon, tilapia and carp. One-year-old salmon fish with growth hormone chimeric gene are able to grow as large as 13 times that of the non-transgenic salmons. Other than that, chicken that can produce eggs containing human proteins has been created by British by transferring DNA into the yolk of a fertilized chicken embryo.
The proteins can be harvested and purified for treatment of diseases such as multiple sclerosis or cancer.