Gene Editing: Building Better Blueprints, One Gene at a Time
The following commentary is from Bob Reiter, Monsanto’s Global VP of Research & Development. The opinions expressed are those of the author.
Ever since its introduction to the world over five years ago, a gene-editing tool called CRISPR-Cas9 has been the scientific breakthrough that everyone is talking about. And while it’s the one generating the most buzz, CRISPR is just one of the gene-editing tools that scientists have been excitedly exploring over the last decade. In fact, more than 11K gene-editing studies have been published since 2010.
It encourages me to see new articles everyday about the latest gene-editing research and potential scientific breakthroughs, particularly in human health care. What draws me into these stories is the great promise that gene editing may enable researchers to treat incurable and fatal genetic diseases, modify human immune cells to kill certain types of cancer cells, and even stop the spread of Malaria, which kills nearly half a million people each year. In agriculture, we believe gene-editing could help cultivate plant varieties that reduce the need for pesticides and don’t require as many natural resources, while also helping farmers grow more crops – which would be a win for both people and the planet.
But as “gene editing” and “CRISPR” become more embedded in pop culture, I sometimes worry that the scientific community isn’t doing enough to adequately help the public understand exactly what this technology does, why it’s something to celebrate instead of fear, and why scientists, like me, are so excited about it.
In many news stories, CRISPR is described as a pair of molecular “scissors” that enables scientists to make precise improvements within DNA, which is often referred to as the “Blueprint of Life.” Other gene-editing tools are said to function more like a “pencil and eraser.” I’m sure most people are quite familiar with scissors, pencils, erasers, and blueprints, but here’s a story that helps bring these concepts together in a more concrete way.
That Time I Built a House…
When I was in my early twenties, I built a house. And I don’t mean that I hired a contractor to build a house, or picked out a floorplan in a new neighborhood development… I mean that I literally drew the blueprints and, with the help of two family members, built the entire house from the ground up.
This is where I should probably remind you that I’m a plant scientist, not a carpenter or construction worker. The biggest thing I’d “constructed” before the house was probably my sixth-grade science fair project, when I built a detailed model of the entire cellular respiratory pathway using only my sister’s college biology textbook as a reference (this was long before the Internet).
Fast forward about ten years to when I won a government lottery for one of a few properties at a new lakeside development in Manitoba, Canada, where I’m originally from. I only had to pay $350 for the land – so taking it was a no-brainer; but the catch was that I had to build a house on it within five years.
I was still in graduate school at the time – needless to say, I couldn’t afford to hire professionals to build the house for me. So, I did what any other financially-challenged, but technically-minded college student would do: I went to the University of Wisconsin library, studied all the construction books I could find in the engineering section, designed and built the architectural plans for my house, and miraculously, got them approved.
Then, over the course of a few summers, my dad, brother-in-law and I brought this dream to reality. Our construction process was slow, but precise. I was the reader and translator of the blueprints, cutting each board or tile to the correct measurements. Then I gave detailed instructions to my “crew,” telling them exactly where each piece needed to go. And eventually, we ended up with a pretty impressive 1,400-square-foot lake cottage that my family still uses to this day.
Everything Hinges on the Blueprint
Over the years, I’ve thought back on that process many times, particularly as I’ve watched the evolution of both human health and agricultural research due to increasing knowledge about DNA and genetic sequencing. Much like the blueprints that informed the building of my house, DNA provides the information for building all the proteins within every living thing on Earth – humans, animals, plants, bacteria, and other single-celled organisms. Proteins are like the building blocks of our bodies. Everything we do is controlled by the proteins within our cells, and each gene in our DNA contains the code for a unique protein structure.
DNA can’t do it all alone; it relies on molecules called Messenger RNA (mRNA) to deliver the instructions for building each protein to the parts of the cells that make them. In my house-building analogy, I was like the Messenger RNA, reading the blueprints and delivering specific instructions for building each piece of the house (or protein) to my crew, which then carried out the orders.
Now consider this: what if there was a defect in the blueprint for the house? If we followed those instructions anyway, the defect would be built into the house – which could later lead to structural problems, ranging from minor to catastrophic, depending on which part the defect involved.
But… if I was able to pinpoint the defect in the blueprint, I could take an eraser and pencil to fix the mistake (or use scissors to snip out the faulty section and replace it), then deliver those new instructions, and my crew would build the flawless version of the house as it was originally intended.
On the other hand, if I wanted to add a feature to improve the house design mid-construction, like adding a kitchen cabinet or moving a wall one inch to the left, I could do the same thing: update the blueprints and deliver the improved instructions to the building crew. It’s important to remember that, relative to the size and complexity of the blueprint, these changes are small and precise. The house as a whole will still stand as it would have before, with one or two targeted improvements having been made.
That is what gene-editing tools are now enabling scientists to do. And the possibility of making improvements never before dreamed about – like fixing rare diseases caused by a defect in the genetic blueprint – is certainly worth getting excited about.
"It will take consumer understanding and acceptance of gene-editing tools and the products they enable for the technology to be impactful across industries and around the world. The only way that will happen is if those of us who have already embraced gene editing can do a better job of communicating with those who haven’t."
The Potential of Gene Editing for Agriculture
Gene editing offers the same exciting potential of newly possible innovations in agriculture. In crop science, we believe gene-editing tools like CRISPR will allow researchers to make precise improvements within a plant’s DNA to:
- Enable a beneficial characteristic (such as drought tolerance or improved nutrition),
- Deactivate an unfavorable characteristic (such as disease vulnerability), or –
- Break genetic linkages between genes conferring positive traits (like disease resistance) with less desirable traits (like drought sensitivity), generating plant varieties with the most desirable combinations of traits.
Basically, these tools have the potential to help plant scientists integrate the most desirable traits into improved seed products for farmers with more efficiency and precision than ever before. And by giving plants a better chance of survival, particularly in regions that struggle with hunger and malnutrition, we will be able to give people a better chance at life as well. As Bill Gates eloquently advocated in a recent article, “…improving the productivity of crops is fundamental to ending extreme poverty… Gene editing to make crops more abundant and resilient could be a lifesaver on a massive scale.”
Gene Editing vs. Genetic Engineering
Since gene editing does not introduce DNA from a different plant species (like “GMO” crops produced by genetic engineering), the end product (edited DNA) is no different than what plant breeders might eventually arrive at through selective breeding for a specific trait. This is why the U.S. Department of Agriculture recently announced that it will regulate gene-edited plant varieties in the same way as varieties bred through traditional methods – a rational, science-based approach that I agree with. Keep in mind that all new plant varieties still go through years of field trialing and safety testing before they are made available to farmers to grow. Gene-editing tools simply help plant breeders achieve the desired genetic blueprint much faster, as well as more reliably and cost-effectively, before seeds advance to the next stage of the development process.
Often I am asked if gene-edited seed products will replace the GMO seeds available to farmers today. (As a refresher, the key difference is that genetic engineering transfers a desirable trait from one species to another, while gene editing makes improvements using genetic material from within the plant’s own family.) I go back to my construction story and consider building my house in a warmer climate. In a “gene-editing scenario,” I could edit the blueprint and redesign the structure to have thicker walls, more insulation, and properly positioned windows. But if I really wanted the house to be cooler, I would need to “genetically modify” the blueprint to include an air-conditioning unit – an external “trait” not included in the home’s original design. So sometimes there are limits as to what we can do to improve a plant by just editing its native DNA sequence, and I foresee a continued need for both types of technology to meet the world’s agricultural challenges.
Communicating the Benefits of a Better Blueprint
Scientific breakthroughs like gene editing are the reason I became a scientist – I’ve always been motivated to do research that helps make the world a better place. The safe and responsible use of these tools can do just that. However, it will take consumer understanding and acceptance of gene-editing tools and the products they enable for the technology to be impactful across industries and around the world. The only way that will happen is if those of us who have already embraced gene editing can do a better job of communicating with those who haven’t. We must help people understand that gene editing works with nature in a way that is safe… and that a better blueprint builds a better house.
Bob Reiter is Monsanto’s Global VP of Research & Development.