What’s CRISPR is it a GMO?

Genetic modification is easy. Perhaps you’ve done it yourself. Are you a gardener? Do you save seeds? If you chose seeds only from the best plants you are modifying the genetics of succeeding generations. This sort of selective breeding has been going on for centuries. It takes generations, but over time plants and animals can be radically changed. Those changes, if they are hereditary, occur in the genes.

Oh, that hardly counts, you might be thinking. It’s slow and is a natural process. I’ll grant you slow, but not natural. Look at teacup puppies and black roses. Think about racing horses whose legs are so thin they break. Natural selection favors those who survive. Artificial selection ignores survivability, in favor of traits that please humans.

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Still, that’s generally not what people mean when they talk of GMOs. In popular usage GMO stands for organisms whose genetics have been modified through introduction of genes from a different species. In this sense wolf – dog hybrids are GMOs. But that still isn’t what people usually mean. Rather they mean laboratory introduced genetics.

For example, a gene from a specific species of fish might be added to a tomato plant to make the tomato more cold tolerant. This raises images of fishy tomatoes, but lets think about what a gene is, starting with DNA.

DNA (deoxyribonucleic acid) is a long thin molecule shaped in the famous double helix. The helix is made of base pairs of nucleotides held together by hydrogen atoms. The order of those pairs determines how they interact with surrounding molecules. A certain sequence will make a particular type of protein which in turn interacts with certain molecules to create a specific effect.

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A segment of base pairs with a specific purpose is a gene. That’s all it is. It can be a section of DNA with a few base pairs up to hundreds of pairs. It’s as if a long piece of string was divided into different colors. Each color segment has a purpose. If you can figure out what the purpose is, you can, in theory, manipulate it.

You will not find a “cold tolerant gene.” What you will find is a section of base pairs which interact with other molecules to create a specific protein. That protein in turn interacts with other molecules in some way which results in greater tolerance for cold. Perhaps it helps in the creation of fat. Or maybe it strengthens cell walls to protect against freezing. In any event, it all starts with the gene and it’s ability to create a specific protein.

The scientist will pluck a specific segment from the fish DNA and introduce it into the tomato. Rather than having a tomato with little fish swimming inside it, you have a tomato with the ability to create a new protein.

GMOs have been around for decades and the research has shown no indication of any related health problems. However, politically and economically I worry about monopolies by giant companies who patent food (look into Monsanto, for instance). But that’s a topic for another post.

This brings us to the newest tool in the GMO business called CRISPR. CRISPR is a revolutionary method which allows for specific gene targeting. Previously, creating GMOs was a comparatively clumsy process. For example, a harmless bacteria might be altered with the addition of a chosen gene, then that bacteria would infect the plant, carrying with it the new gene.

CRISPR makes it possible to literally cut and paste specific genes. A section of DNA can be cut out and / or replaced with a new section. The technique is comparatively easy and cheap. Although it’s only been around for a few years, CRISPR is already being widely used. It is popular for traditional GMOs and as well as in industry, but increasingly CRISPR is being used on people. China was the first, beginning with non-viable human embryos. More recently studies have begun on cancer patients. Although it is too early to know what the results will be, this clearly marks a change in our ability to manipulate our own genetics.

On the one hand, it could be possible to cure genetic diseases, on the other hand, it’s equally possible to create “designer babies.” The question is: are we as a species wise enough to take evolution into our own hands?

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Thanks for reading,
Kate
June 12, 2018

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