 Genetically modified organisms, or GMOs, have had their DNA artificially modified by humans, using modern genetic manipulation techniques. By changing the DNA, so changing the genome of an organism, means we can change its characteristics. Humans have been artificially altering the genomes of plants and animals for thousands of years by selective breeding. Today, with advances in genetic engineering techniques, means we can speed this process up by incorporating specific new genes from one species into a completely unrelated species. Crops, farm animals and soil bacteria are three of the most common uses of genetic engineering to make GMOs. The cotton plant that grows the cotton for your t-shirt might have been genetically modified to be pest resistant, or the bacteria modified to produce life-saving medicines, as well as the better-known GM crops that we eat. And then there's some wacky organisms like spider goats and glow-in-the-dark mice. Firstly, let's find out how genetic modification happens. The short answer is there are a couple of different ways. There are several techniques that can be used to modify a genome, but the main one relies on bacteria. Bacteria are single-celled organisms that don't have a nucleus like our cells, but instead have one main circle of DNA called the circular chromosome, and lots of tiny circles of DNA called plasmids. In GMOs, it's all about the plasmids. They are really useful tiny bits of DNA that can contain one or several genes. The cool thing about plasmids is that they can be passed between bacteria as easily as shaking hands. So plasmids are a super important part of how genetic modification happens. Let's go through the steps using the human insulin gene as an example. First, we cut the gene for human insulin from a human cell using an enzyme. We then use the same enzyme to cut the circular bacterial plasmid open and stick the insulin gene and the plasmid together. Then we put the modified plasmid back into a bacterial cell and we wait, but not for too long as bacteria cells divide roughly once every 30 minutes, and a little while later we have millions of bacteria producing the human insulin protein and excreting it. The human insulin is filtered out and purified and can then be used by people with diabetes. How simple is that for saving lives? Spider goats are also a great example of a genetically modified organism. They aren't as scary as they sound. They're goats that have had the spider silk gene inserted into their DNA, so when female goats lactate, produce breast milk, the milk contains spider silk. The spider silk is pretty incredible. It's as strong as steel, but so light that a strand long enough to circle the earth would weigh less than 500 grams. So there are thousands of uses for such a unique material. Scientists have used genetic modification to introduce genes that glow under UV light, such as from jellyfish into other animals for medical research. This may seem totally useless, but actually, being able to see certain cells in the dark has led to a lot of scientific discoveries. Glowing the dark mice and fish have helped scientists make new breakthrough research into treating cancer, Parkinson's and spinal cord injuries. And glowing the dark cats have been used for HIV research. Cropped can also be genetically modified to make them more pest resistant, to have nutritional benefit like additional vitamin A. To learn about GM crops, watch this video. So there we have genetically modified organisms that have had their DNA modified for some different uses.