Nature Creates Its Own Genetically Modified Organisms


The Washington Insider reports: 

The Wall Street Journal has been none too happy with the GMO label debate, often suggesting that the modification process itself is not a characteristic that deserves to be labeled. Recently, it followed up on that argument with an article suggesting the “natural horizontal gene transfer” is common, information that “could undermine arguments against genetically modified foods.”

Scientists have now discovered a way by which genes from one species “can jump directly into another species,” the Journal says, and calls that “nature's way of creating genetically modified organisms.”

The finding is relevant to the debate over genetically modified food labels, the Journal says. Some opponents frequently maintain that an interspecies gene transfer done in a laboratory such as the insertion of a bacterial gene into corn to make it insect-resistant, for example, “would never occur naturally and is therefore unethical and potentially unsafe.”

It now is pointing to a new study, published recently in in the journal PLOS Genetics, that undermines such an argument. “You realize that nature is creating genetically modified organisms all the time,” said Salvador Herrero, a geneticist at the University of Valencia, Spain, and co-author of the study. “It's not so weird to transfer genes from one organism to another.”

Genes are typically passed on within the same species, from parents to young, a process known as vertical gene transfer. But in recent years, scientists have pinpointed many instances of horizontal gene transfer, which involves genes moving from one species into an entirely unrelated species that happens to live in the same environment.

For example, a gene from a species of bacteria has been discovered in the genome of the coffee berry borer beetle, where it enables the beetle to feed exclusively on coffee beans. It is through horizontal gene transfer that bacteria typically develop antibiotic resistance.

A few months ago, a team of UK researchers concluded that the “jumping gene” method enabled humans to acquire more than 145 foreign genes from bacteria, viruses and fungi over the course of our evolution.

Still, it has been a mystery regarding how this can happen. In the latest study, researchers suggest a possible route whereby the genes of parasitic wasps invade the genomes of butterflies and moths. “When braconid wasps lay their eggs inside caterpillars, they also inject a virus from their bodies to incapacitate the caterpillar's natural immune response. This allows the wasp larvae to feed on the caterpillar unhindered. In the process, genes that belong to the wasp and are harbored by the virus also end up in the caterpillar host.”

The larvae thrive but the caterpillar dies. In this scenario, the inserted wasp genes go nowhere. But sometimes, the authors say, “the parasitic wasp may attack a non-host caterpillar.” Although its eggs won't survive in this creature's body, the inserted wasp genes integrate with the caterpillar's DNA and are transmitted to future generations of butterfly progeny. Thus, the presence of wasp genes in butterflies.

Scientists know the integration happens because sequences of the wasp's DNA have been found in the caterpillar genome. But the precise mechanism is still uncertain.

In most documented examples of horizontal gene transfer “we know that a gene doesn't belong,” said Louise Johnson, evolutionary biologist at the University of Reading, who wasn't involved in the research. “This is a good study because it tells us exactly how the gene transfer occurs.”

The authors say they discovered wasp genes in two species of butterflies, including the familiar orange-black-and-white Monarch butterfly common in North America, and in three species of moth, including the silkworm.

Genes typically persist if they provide some benefit, scientists say. According to the PLOS study, two of the genes acquired from wasps produce proteins that protect caterpillars against a foe known as the bracovirus. They do so by hindering the bracovirus's ability to infect the caterpillar and by interfering with the virus's ability to replicate.

So, what does this mean? Certainly, the process of genetic modification has been important in the development—and improvement—of food and fiber products for many, many generations and the rules that govern such processes are becoming increasingly familiar to scientists. And, it means the efforts by activists to find a simple, perhaps damning label that will protect consumers from both real and imaginary threats seems increasingly unlikely. What will change that? Possibly, a miracle gene that provides a real, otherwise unavailable benefit for a lot of consumers.

Or, the dumbed-down regulatory process that labels everything without meaning anything much could be seen as “not worth the trouble.” Certainly, the labels activists thought would allow them to elevate their undocumented “concerns” to the point where consumers would reject the technology seem to be falling far short.

So, now it is USDA's chance to design labels that are fair and informative—a challenge the agency failed on the Country of Origin labels at significant cost to the industry. 



Source:  DTN Washington Insider



Pixabay photo  CC0 Public Domain

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