Undeniable (29 page)

In the case of predator and prey on the wide-open savannah, we're talking about physical abilities. But the same process unfolds in many other ways right here in human society. You know the old saying, “Keeping up with the Joneses.” We send each other signals continually. We acquire titles and material goods to let others know our value or status relative to everyone in our tribe. We can all understand the urge. It's a human version of peacock feathers, or moose antlers, or the giant neck frill of the Triceratops, or any of a million other types of costly signaling that animals do or did.

If someone else has acquired a new phone or lawn mower that clearly performs better than the one you're using, you want it. From there, it's a small step to feel the urge to be out in front, to make other people want what you've acquired. It costs you something, but you're sending a signal—an evolutionary signal—flashing across deep time.

 

30

GENETICALLY MODIFIED FOODS—WHAT THE GMF?

If you ever visit Salt Lake City, Utah, I encourage you to drive to Temple Square; it's on North Main just south of Temple Street. There you will see the Seagull Monument, a bronze sculpture atop a granite column commemorating what certain believers call the Miracle of the Gulls. In 1848, Utah farms were attacked by hoards of katydids, insects related to grasshoppers. A group of California gulls showed up and reportedly ate a great many of the katydids. Locals, who were generally of the Mormon religious sect, considered it a miracle. The gulls are the Utah state bird, and there was nothing extraordinary about their presence there, but people took this katydid business very seriously because the threat from insects was so great. By some accounts, the Mormons stood to lose a year's supply of food in less than a week. They built a monument, after all.

Today, farmers cede an average of 13 percent of their crops to insects. It is a serious, serious business. In the 1990s diligent biologists addressed this problem in an evolution-based dramatic new way. Researchers developed ways to extract genes from one species and insert them into the genetic code of another—a technique that can, among other things, cause invading insects to kill themselves.

The organisms produced in this fashion, which we eat, are called Genetically Modified Organisms or GMOs, sometimes Genetically Engineered Organisms (GEOs) or, for this chapter, Genetically Modified Food (GMF). These days, the term is probably most familiar from the “Non GMO” labels slapped on many organic foods, inspired by fears that genetic modification makes things unsafe to eat.

Genetic engineering is a kind of artificial selection, but it's quite a bit different from the breeding traditionally done by farmers, arborists, and dog fanciers. GMOs end up carrying combinations of genes that would not naturally occur inside the cells of any organism. Scientists armed with a rich understanding of the DNA molecule have managed to combine genes from species that would never cross paths in nature, species that could never even be successfully “crossed” in the Darwinian sense by human breeders.

We've been heading down this path for a long time. Have you ever encountered a clone? You may think not, but I'd be surprised if you haven't seen one and enjoyed its fruits. Almost all the strawberries in the world are grown from plants that farmers cultivate by letting the shoots or runners (rhizomes, technically) grow out from a parent plant. The plants that take root from these runners are genetically identical to the parent. Such offspring are called clones, which comes from the Greek word for “twigs.” Most grape vines are cultivated in a similar way. Wines are therefore the product of this kind of cloning. It's not an inherently bad thing, especially if you enjoy a good Cabernet. It's just that these days we are able to produce clones artificially, without a parent or predecessor as such. This is another area in which science is wresting control of the genome away from natural evolution.

You may have heard of Dolly the sheep, the first artificially cloned animal. She was produced back in 1996 by putting the DNA from a single cell of one sheep into the egg or ovum of another sheep. That artificially fertilized egg was then implanted in the uterus of a ewe who gave birth to Dolly. In other words, Dolly was genetically identical to her mother, or at least she had exactly the same sequence of genes in her DNA as her genetic mother. Her genes were independent and unconnected to the ewe who gave birth to Dolly. That sheep was what we call a surrogate for what would have been Dolly's traditional biological mother. There was some compelling evidence that Dolly seemed to have been born old, in a genetic sense. There were some chemicals on the ends of her chromosomes called “telomeres” that were shorter than researchers would expect in a newborn. Otherwise, Dolly is and was a regular sheep. She gave birth to six lambs over three seasons, and her descendants still frolic in the Scottish hills today.

To produce Dolly, researchers at the Roslin Institute in Scotland used the DNA from just one cell from a mammary gland of her mother. A cell that forms the body of an organism is called a somatic cell. Most of your cells are somatic; the only exceptions are stem cells and reproductive cells. They say that Dolly the sheep was named for Dolly Parton, who along with a wonderful voice and excellent musical artistry has memorable mammary glands. (I am not kidding; that's really what the Roslin scientists told reporters.) The process was mechanical. The researchers used a long, amazingly thin pipette to poke the DNA into the egg. It was not an easy thing to do. Dolly is the result of implantation number 277, a success that was preceded by 276 failures.

Although it is quite difficult, this type of genetic modification or engineering is, for me at least, relatively easy to understand. We take DNA from one organism and physically or mechanically put it in another. They were both sheep, both the same kind of organism. But there is a more subtle kind of genetic manipulation that researchers have developed in recent years. This is the work that has led to the creation of GMOs.

There is a way to insert genes into organisms without fertilizing, prodding, or poking: Genetic engineers turn to viruses to do the work. There are certain viruses known to infect plants, for example. Scientists use viruses like these to introduce genetic traits of their choosing. First they splice a desired gene into a virus. Then they infect the plant with the engineered virus, which inserts the gene into the plant's DNA. This technique has been widely applied to corn, soybeans, canola, squash, sugar beets, cotton, and papayas. Along the way, GMOs have sparked controversy for a couple of different and important reasons, one having to do with business, the other with evolution.

The evolutionary concerns revolve around the effects of introducing fundamentally new types of crops into the environment. For instance, scientists have been able to isolate the gene from a bacterium called
Bacillus thuringiensis
, which occurs naturally in the soil around corn plants, and inject it into the corn itself. The reengineered crop, called Bt corn, then produces a chemical that paralyzes the digestive system of European corn-borer caterpillars, causing them to starve to death. Everyone you've ever met has probably eaten food that carries this gene, a gene previously restricted to the bacterial world. About 90 percent of the corn and 93 percent of the soybeans now consumed in the United States are a product of genetic engineering; about 70 percent of processed food includes GMO ingredients.

Researchers have been able to produce varieties of soybeans, canola beans, and corn that make the plants able to thrive even in the presence of the deadly Roundup brand of herbicide. The agricultural seed suppliers charge a good deal extra for this feature, which dramatically increases a farm's yield. If those plants produce seeds that blow into another farmer's field, does the farmer have to pay the seed company a licensing fee? These are the kinds of issues that agricultural businesses are grappling with today.

There is no question that the genetic modification of crops has enabled farmers to feed a great many more people using just a little bit more land. The reduction of losses to pests makes for an almost 30 percent increase in farm yields compared to a century ago. There is controversy about the numbers, but in principle, corn that produces its own insecticide allows farmers to spray less toxic chemicals on their fields. On those grounds, genetically modifying crops seems like a great thing. But many people are opposed to the practice all the same.

Genetically engineering food is controversial, as it should be. If you're asking me, we should stop introducing genes from one species into another, while at the same time taking full advantage of our ability to understand the genome of any organism—plant, animal, or fungus—in order to produce the healthiest, most sustainable food system possible. Here's why: Although we can know exactly what happens to any organism we modify, we just can't quite know what will happen to other species in that modified organism's ecosystem. For me this is a big deal, though some other investigators don't seem to find it as troubling.

Let's look at one well-studied example. Monarch butterflies make an extraordinary four-thousand-kilometer trip from Canada to Mexico every year. When they emerge as caterpillars, they feed on milkweed leaves. (I'm sure they're delicious—the milkweed leaves.) The herbicide Roundup, used by corn farmers to improve productivity by killing weeds, also kills milkweed plants. Genetically modified corn that resists Roundup has also been developed, which enables corn farmers to use more of the herbicide instead of tilling their fields. That practice seems to be inadvertently eliminating large areas of potential Monarch butterfly breeding habitats. There's still controversy about whether the use of Roundup is actually reducing Monarch butterfly populations.

Wait … there's a little bit more! There have been some claims (controversial ones, admittedly) that when pollen from genetically modified Bt corn blows onto the milkweed, it can make Monarch caterpillars sick. If that's true, then the genetically modified plants are coming after the Monarchs in two ways at once. What is an industrial farming society—one with a deep understanding of evolution—feeding millions of people around the world, supposed to do? Certain modifications allow us to use smaller amounts of pesticides to raise crops. Producing a sufficient supply of food is an urgent need. It can be a tricky issue. Nevertheless, I still like to evaluate GMOs with the ecosystem in mind.

Consider yet another example. Papaya grown in Hawaii are susceptible to a virus that causes dark circular spots to appear on the fruit. It is appropriately called the “ringspot virus,” virus family
Potyviridae
. Researchers found that by putting a piece or section of the virus's DNA into the papaya's DNA, the papayas are no longer susceptible to infection by that particular virus. You don't have to know anything about papaya or fruit or GMOs or farming to tell the difference between a ringspot-infected papaya and a healthy one. There is no question in your human animal mind of which one looks like it would be better to eat.

But there's a little more to the story. There is evidence that by producing a papaya fruit that is not susceptible to ringspot, the papaya plant becomes somewhat more susceptible to another parasite called the blackspot fungus. Furthermore, there is apparently some evidence that some people are allergic to the genetically modified papaya, while not being allergic to the fruit of the premodified, natural plants. In other words, it's complicated. That's the way things are when you change the inputs in an ecosystem. Evolution itself is complicated.

There are also cultural and economic reasons for caution. Case in point: Researchers successfully developed a certain breed of tomato that was far less susceptible to freezing on a cold morning than traditional tomatoes. They did it by arranging for genes from a fish, the winter flounder, to be inserted into tomato genes. These fish, which are pretty common off the coast of the U.S. and Canada, can handle very cold water. The fish gene helped the tomato handle very cold air. That in itself is remarkable, a tribute to our deep scientific understanding of DNA and the effects it can produce for an organism's interaction with the environment. But there is something weird and unnatural about putting fish genes in fruit, in tomatoes. Nobody wanted it, so that research was abandoned.

I'll grant you, this could be a visceral reaction from ignorant consumers. Emotional responses do not necessarily reflect scientific reality, as is evident in everything from creationism to the anti-vaccine movement. In this case, though, I think science and emotion are on the same side. There are very valid scientific reasons to approach GMOs with caution, and those turn out to dovetail with economic reasons. So far, it's not clear that investment in GMOs pays off. It's certainly not clear that GMO research should be funded with tax dollars. If nothing else, the ubiquity of corn and corn syrup has helped to create the weird situation in the developed world, the U.S. especially, of fat people who are malnourished.

Here's one example of how science and economics are getting intertwined. No matter how you feel about fast food, no matter how focused you may be on avoiding fats and carbohydrates, French fries are just delicious. The fries are what keeps me interested in McDonald's restaurants, and I know I'm hardly alone in this abiding interest. McDonald's investigated the possibility of sponsoring research into a genetically modified potato that might make their French fries better and more economical to produce. This was the NewLeaf potato. The company surveyed its customers, asking essentially, “If our fries were even better than they are now, but produced from genetically modified potatoes, would you want them, or even want them all the more?” The answer was a resounding “No!” So McDonald's, the world's largest fast-food restaurant chain, decided not to fund research into GMO potatoes.

That decision essentially killed the research into messing with potato genes—for a while. As I write, there is a new McDonald's GMO controversy, this time surrounding a different modification to potato genes. Certain genes that may lead to the production of a carcinogen when cooked would be “silenced,” or turned off, via genetic engineering. Much like last time, the genetic modifiers believe their potatoes are safe to eat. In my opinion we still can't be sure what will happen to the ecosystems out there. The possible consequences give me great pause.