GM CROPS PART 1: What are GM crops?

Other articles in this series:
Part 2: Why do we need to improve our crops? What's wrong with the way they are now?
Part 3: What have GM crops done so far?

What are GM crops?
GM stands for 'genetically modified'. This post explains what that means.

Every living thing contains a set of instructions that tell it how to be itself. These instructions are called 'genes'. An elephant has a set of genes that tell it how to be an elephant. An oak tree has a set of genes that tell it how to be an oak tree. A bacterium has a set of genes that tell it how to be a bacterium.

Most living things have thousands of genes (a human has about twenty thousand) and each gene is the instruction for doing one particular thing. If you compared the genes in two different living things (a cat and a sunflower, say), you would find that there are quite a lot of genes that they have in common. This is because there are many things that they both need to do. For example, a cat and a sunflower both need to burn food to release energy. In order for a living thing to burn food it needs to produce a set of tiny machines called 'enzymes'. Therefore the cat and the sunflower both have genes that tell them how to produce these machines. However, there are obviously also a lot of differences between a cat and a sunflower, so they don't have all the same genes. A cat has genes that tell it how to make eyes, a sunflower doesn't. A sunflower has genes that tell it how to make petals, a cat doesn't. It is a living thing's complete set of genes that make it what it is. A living thing's complete set of genes is called its 'genome'. 

All of the genes (instructions) that exist are written in the same language (the language of DNA). This means that if a gene is transferred from one living thing to another it will still work. This happens naturally all the time because viruses and bacteria are able to physically move genes from one living thing to another. For example, bacteria regularly pass useful genes on to each other (such as genes that allow them to survive antibiotics). It isn't just tiny bacteria that share genes though, all living things do it. For example, it has recently been discovered that a quarter of the cow genome was transferred over from a snake!

Scientists have found their own ways of moving genes from one living thing to another. This means that we can add genes to crops (the plants that produce our food). We can give a crop a new gene that we have taken from another living thing. This new gene tells the crop how to do something that it couldn't do before. The crop is now called a 'genetically modified (GM) crop' because it has had its genome modified. 

Click here to read Part II. It's called 'Why do we need to improve our crops? What's wrong with the way they are now?'