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Gene Editing: Key Messages in Elevator Pitch
Adrianne Massey, PhD BIO Consultant 2018 SD Biotech Summit & Annual Meeting
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Gene edited food and ag products being developed
Mastitis resistant livestock Bird-flu resistant poultry Swine fever resistant pigs Omega-3 swine Fruits/vegs that stay fresh longer Low gluten wheat Allergen-free milk, eggs and peanuts Disease-resistant fruits and vegetables All of these products have already been developed with genetic engineering (rDNA technology). They were not commercialized Biotechnology Innovation Organization
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How to frame gene editing
Making specific, precisely-targeted changes to an organism’s own genes; Gene editing is not about adding “novel” genes from “other” species; Gene editing is about working within the “species” gene pool; does not lead to “transgenic” organisms.
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How to talk about gene editing
They may want to talk about “CRISPR” CRISPR is just a tool Talk about the applications of the tool (products being developed; benefits) Describing the applications provides the context Biotechnology Innovation Organization
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How to talk about gene editing
Gene Editing Tools CRISPR, CRISPR-cas, TALENs, Zinc fingers nucleases, Meganucleases …. All are naturally occurring, biological molecules that make specific changes. Gene editing occurs constantly in nature.
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Distinguish tools from functions
CRISPR; CRISPR-cas; TALENs, Zinc fingers, Meganucleases …….. can be used to do many things, one of which is to edit genes (i.e., make precise, directed changes in an organism’s own genes).
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Is a gene edited organism a GMO?
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Is a gene edited organism a GMO? How to answer if person:
1. truly wants to understand, or 2. wants a soundbite (7 seconds)
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Defining Genetic Modification
Genetically Modified Organism - “GMO” An organism with genetic material that was modified intentionally by humans
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Defining Genetic Modification
We rely on biological organisms for all of our basic needs: food, shelter, clothing, environmental management, energy, good health. We have genetically modified every organism we rely upon – plants, animals, microbes – for thousands of years Remember your primary goal is to provide context for people who know little about biology or ag but who want to learn. I’ve found that with lay audiences you often need to remind them that plants, animals and microbes have always helped us meet our need for food, shelter, clothing, energy, good health, and environmental management and therefore biotechnology has a very long history The most important message you can leave them with is that we have changed the genetic make-up of every organism we use – plant, animals, microbes Biotechnology Innovation Organization
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THE most important message:
If GMO means an organism with genetic material that was modified intentionally by humans, then - people have been consuming GMOs for over 10,000 years - All of the organisms we rely on are “GMOs”
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History of Genetic Modification in Ag
- Domestication is genetic modification - Certain individuals had traits we valued - Valued individuals were parents of next generation Genetic modification of the population through selection
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“Non-GMO” fruits from the wild ancestors of our crops
Banana Corn Tomato Cucumber
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History of Crop Genetic Modification
Genetic modification through selection Genetic modification through cross breeding (began in 1600’s). In cross breeding, humans, not nature, decide which individuals interbreed.
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Cross breeding within species
X Good taste Susceptible to disease Bitter taste Resistant to disease Good taste Disease resistance Cross breeding combines thousands of genes.
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Cross breeding - Different species
Began in 1700’s Includes “wide crosses” that would not occur naturally Some varieties of all major crops came from combining genes from different species. Successful cross breeding across different genera began in 1800’s Examples of traits we have incorporated into crops by forcing interspecific crosses Corn Fungal disease resistance Canola Altered fatty acid ratios Oats Increase yield 25–30% Beets Nematode resistance Tomato Virus resistance Harvesting traits Nematode resistance Fungal disease resistance Rice Virus resistance Potato Fungal disease resistance Virus resistance Insect resistance Wheat Fungal disease resistance Increase protein Drought tolerance Winter hardiness
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Cross breeding across genera
Starting in late 1800’s, plant breeders have crossed bread wheat with at least eleven different species in six different genera. Traits: resistance to insects, disease and drought; winter hardiness; increased protein
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Cross breeding - Different genera
intergeneric cross Same genus Different species Same species Different genus Same family Different Family
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Genetic modification via mutagenesis
When desirable genes are not available: Breeders create new genes with mutagens, such as X-rays or chemicals. This form of genetic modification is mutagenesis breeding. When desirable genes are not available either because the genesdon’t exist (or we haven’t found them) or they exist but are in organisms that are too distantly related,i.e, not in the same genera when its plants
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Genetic Modification through Mutagenesis
Since 1930, plant breeders have used mutagenesis to create thousands of crop varieties that were introduced to the food supply.
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Conventional Plant Breeding Continuum of Genetic Modification Technologies
8000 BC ’s late 1700’s late 1800’s ’s Selection Cross-breeding Cross-breeding Cross-breeding Mutagenesis within species b/n species b/n genera Two themes/strategies to crop improvement: -Combine existing genes/Bring existing genes into crop -Change an organism’s own genes Let’s review the history of conventional breeding. Even though this slide is labelled plant breeding, these steps and general themes apply to animal breeding as well. Some of the later dates apply primarily to plant breeding. For thousands of years, humans selected whatever genetic diversity mother nature provided – whether through combining existing genes or natural spontaneous mutations. Indicated by green. This selection of certain genetic types led to domestication of crops and animals and specialization of plants and animals into varieties and breeds Once we found out how plants and animals reproduce (in other words, once science began to inform plant breeding in the 1600’s) we began to selectively breed certain individuals that had traits we preferred. Combining existing genes to create genetic diversity – indicated by yellow type. We improved our specially adapted varieties by intentionally bringing in genes from same species, then different species (true for plants and animals; remember the Brahman (indicus)-Angus (Taurus) example); then different genera (in plants not unusual; very rare in animals). But then we ran up against the taxonomic boundary. Therefore, because we still needed to improve our crops and livestock, we began to create new genes or new forms of exiting genes with mutagens (true in plants and animals, but much, much more so for crop plants than livestock; however mutagenesis to create new traits is very common in research animals like mice, rats, and insects)
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Key Message: Conventional plant breeding has very long history of safe use Not a single instance of harm to human health or environment from new varieties Thousands of new plant varieties introduced every year
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Continuum of Genetic Modification Technologies
8000 BC ’s late 1700’s late 1800’s Selection Cross-breeding Cross-breeding Cross-breeding Genetic w/in species b/n species b/n genera Engineering People seem to use “GMO” to mean a “genetically engineered” (GE) organism. GE and cross breeding use genes that occur in nature. The next step in the continuum of genetically improving our agricultural species by bringing desirable genes our crop varieties and animal breeds is genetic engineering. Modern molecular techniques have allowed us to bring in a new gene from any species into the plants and animals we use. There are no taxonomic barriers. This is why you will hear biologists say, GE is the next step in a continuum. They are bringing in genes that already exist to create crops, like Bt corn, or animals, like the AquaBounty salmon. People will say it’s not natural to put a gene from a bacterium (Bt) in a corn plant. Biologists will respond by saying Breeding stopped being natural centuries ago, and You would be surprised how often Mother Nature ignores taxonomic barriers and moves genes between organisms like bacteria and plants or viruses and insects. So, genetic engineering is like breeding because you’re bringing new genes into your highly specialized variety. The difference is that there are no taxonomic barriers to gene transfers.
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GE and Breeding Cross breeding combines
- thousands of genes of - unknown functions Genetic Engineering adds - 1-2 genes of - known function GE is more precise and more predictable. No taxonomic limits with GE.
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Continuum of Genetic Modification Technologies:
Changing an organism’s own genes 8000 BC - Present ’s ’s Selection-spontaneous Induced mutations Gene/Genome mutations with chemicals/X-rays Editing If genetic engineering is most like cross-breeding because the breeder is bringing new genetic material into plant varieties and animal breeds, then gene editing is most like mutagenesis because the breeder is changing the organism’s existing genes.
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Gene editing is like mutagenesis
Gene Editing – making specific, targeted changes to an organism’s own genes. Gene editing is more precise than conventional mutagenesis breeding.
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Is a gene edited organism a GMO?
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Does gene editing create GMOs?
If asked this question, here’s what my soundbite would be: “If by ‘GMO’ you mean a plant or animal that contains ‘foreign’ genes, then no, gene edited products are not GMOs.” “If by ‘GMO’ you mean a plant or animal with genes intentionally changed by humans, then yes,but that’s true of all of the food that all humans have eaten for many centuries.”
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Key Messages: Human Health and Gene Editing
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Human Health Applications
Always distinguish germline changes in genetic material from somatic cell changes. Germ cells – eggs, sperm, fertilized egg Somatic cells – all of the other cells [Soundbite word choice – fertilized egg, not embryo] To a scientist a fertilized egg and all subsequent developmental stages are called embryos. However when most people hear “embryo” they visualize a fetus. For lay audiences, fertilized egg is actually a better term to use for the earliest stages of development (fertilization – 14 days) because it is not misleading; it still encompasses the concerns of those who believe life begins at fertilization.
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Human Health Applications
Somatic cell genetic changes are not inherited Remove bone marrow cells (stem cells) or T-cells Gene edit to treat disease Reintroduce edited cells to the bone marrow cavity. HSCs or T cells Cells Removed Genetic Modification Reintroduced IV Infusion Context: - Bone marrow transplants - Gene Therapy via “genetic engineering” ’s
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Historical context – GM in humans
Game changer in human applications – IVF Electron micrograph of a blastocyst IVF - pre-implantation disease diagnosis. Some embryos are selected for, some against. With respect to human applications of gene editing, think back to that continuum of genetic modification we discussed for plants and animals that began with different genetic combinations created by breeding and the subjected to selection…. We said it is critical to differentiate germline from somatic cell genetic modification because germline genetic modification has the potential to change the genetic makeup of the species. That potential already exists and is being acted upon– not by genetic engineering or gene editing but by simple selection -- artificial selection by humans.
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Thank You!
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