It’s hard to find a pantry or refrigerator anywhere that doesn’t contain food that wasn’t grown, formulated with or fed a GMO (genetically modified organism). And that freaks a lot people out.
In short, GMO is a laboratory process of taking genes from one species and inserting them into another in an attempt to obtain a desired trait or characteristic – or simply turning on or off existing genes. And yes, this is different than grafting trees or breeding animals that farmers have been doing for eons. The difference, of course, is farmers are not trying to cross a tomato with a chicken – but the lab coats have been pulling off similar genetic tricks for some time and with increasing frequency.
People who are concerned with genetically altered “things” are most concerned about food – more specifically the seeds used to grow those foods. The vast majority of the soybean and a big chunk of the corn in the U.S. are grown with GMO seeds (seeds patented and sold by the easy-to-hate Monsanto folks). While eyebrows raise when the discussion turns to genetically altered animals, like in the case of pigs that have been tinkered with to better digest phosphorus and thus reduce environmental impact associated with pig poo, tinkering with good old wholesome grains, potatoes, papaya, squash, and tomatoes concern a great many more people and governments.
At issue is gene transfer. For example, since Atlantic salmon only feed during spring and summer, researchers modified the genetic makeup of the fish by adding a growth hormone regulating gene from E. coli plus some mouse DNA. The genetic gymnastics enables the fish to eat year-around and presto, a fish that grows and reaches market faster. The big and legitimate question on everyone’s mind is what would happen if one of these Frankenfish got loose and mated with a wild salmon. Would this in some way adversely affect wild salmon populations?
If “horizontal gene transfer” were to take place, between say a genetically modified plant like corn or our salmon, might the gene gone wild have an adverse affect on the person who consumes it? That is, will this novel genetic material worm its way into our own genetic material and do something unexpected? The honest truth is we don’t know for sure. Therefore many think we must ban GMO crops and animals both modified and fed modified crops until we do know. The scientists on the GMO is okay side of the fence, and it includes bus loads of researchers who don’t work for seed companies, say that while horizontal gene transfer should be studied, it is unlikely to be an issue as its probably been very common throughout mammalian evolution.
While turning genes off and on is common in genetic research, using genes from bacteria for certain outcomes is more relevant to GMO discussions. So when we talk about GMO foods, we are – for the most part – talking about genes that have been harvested from bacteria and inserted into the target microorganism (say corn seed) to achieve a preferred trait or outcome. With most GMO corn, the donor organism is a harmless soil bacterium (Bacillus thuringiensis) and a gene that produces a protein that is highly effective at killing caterpillars. Harvest that gene from the bacteria and splice it into corn seed DNA and bam, dead caterpillars and higher crop yields.
Sense the issue surrounding the safety and efficacy of GMO is centered on bacteria – and whether or not we can uptake these novel genes into our own genome – an astonishing finding in Japan surrounding sushi consumption is worth considering.
Reporting in the journal Nature, researchers studying how ocean bacteria break down marine algae (seaweed) discovered that a certain strain of bacteria (Zobellia galactanivorans) produce special enzymes that break down carbohydrates in seaweed into packages the bacteria could utilize as an energy source. It seems that when humans started inhabiting the island of Japan some 40,000 years ago, they began ingesting this marine microbe on slivers of seaweed and in the process introduced the special carbohydrate-reducing enzymes to bacteria that lived in their own guts.
Interestingly, since none of the normal (commensal) bacteria in the ancestral Japanese gut bacteria contained the genes to produce the special enzymes needed to break down the seaweed – and thus release it’s nutrient value – bacteria in the Japanese gut simply borrowed genes from the marine bacteria hitch-hiking on each mouthful of seaweed. Since the Japanese, then and now, consume sushi wrapped in seaweed, the evolutionary pressure to keep the horizontal gene transfer going persisted.
When the researchers tested for the presence of this special enzyme in the gut microbiome (collective genomes of all the bacteria in the human gut) of 13 Japanese volunteers, it was present in every person. Astonishingly, the enzymes were also found in gut bugs of newborns that had obviously never eaten sushi. This suggests that bacteria containing these special genes were transferred vertically from mother to child during birth. When the researchers tested 18 folks living in the U.S., they could find no evidence for the special seaweed-eating genes.
The clear-cut horizontal gene transfer of seaweed-eating genes from marine bacteria to human gut bacteria is more or less what the GMO proponents fear the most. In the case of the Japanese, whose ancient and modern diet include significant amounts of seaweed in soups, garnishments, and wrap for sushi, the gene transfer was facilitated and maintained by evolutionary forces. That is, the human gut microbiome with its trillions of inhabitants did not possess the genes to produce the special seaweed-degrading enzymes, so it simply borrowed them from marine bacteria – and then proceeded to pass them down through generations. In other words, there was a benefit to do so – in this case, maximizing calories from seaweed.
Equally important is the fact that Western populations do not possess these genes within their gut microbiomes. Why? Even though westerners have eaten seaweed throughout history, it has not been important enough in Western diet for the bacterial genes from the seaweed-eaters to take hold and persist. In other words, there was no benefit to the host. And for modern Western populations, even less so given that the seaweed that is wrapped around most modern sushi has been heated, and therefore all the marine microbes terminated from the heat.
The horizontal gene transfer from marine bacteria to human microbiome was a first for science – but likely not the last. This example eloquently demonstrates the important role of the gut microbiome in our evolutionary success as a species and clearly demonstrates that gene transfer likely only takes hold if the host genome or microbiome perceives a benefit.
As we continue to scrub the microbes from our daily lives – through antibiotics, wet wipes, and hyper-sterilized, cooked, and cleaned food supply – what important gene transfer events are we wiping away?
*Note: all of the seeds and grains in our Ancestral Blend are grown with nonGMO seeds.
Doesn’t the title read oddly? Perhaps I am understanding it wrong but it poses a question about “the Japanese” which makes me thing you are referring to the Japanese people.
I hope this doesn’t confuse more.
-A Naked enthusiast