(Source: wikipedia.)

(Source: wikipedia.)

Some say that genetically modified plants are a concern because they’re genetically modified organisms (GMOs), that “natural” plants are safer.

Yet what most people call “natural” foods are rare mutants that have been selected or have been artificially bred (or often both). They have much more dramatic genetic changes than GMOs. Changes that scientists are still learning about.

Foods we eat today bear little resemblance to the wild species they were originally derived from. Even plants that we might not at first consider to be cultivated have been selected for many hundreds or, more usually, thousands of years.

This line of thinking always reminds me of Christian evangelist Ray Comfort’s “designed” banana: natural wild bananas are nothing like the edible fruit.

Wild bananas produce small fruits with large hard seeds and are essentially inedible (or at least unpalatable!). Ray’s “made for man” banana is man-selected cross of red and green bananas that has been bred over thousands of years resulting in a pollen-less, seedless fruit. Our food banana is a genetic mutant on a giant scale, triplicating it’s entire genome.

(Source: wikipedia.)

(Source: wikipedia.)

In a similar way, the wild counterparts of the tubers we eat today are tough bitter roots compared to the large fleshy crops we now take as “natural”.

Calling, say, modern orange carrots “natural” is as wrong as Ray calling bananas “designed”. (Orange carrots were bred to honour the Dutch House of Orange.)

It’s understandable, though. Most of us haven’t seen anything else and we don’t think much about where they came from.

You’ll tell me that our food is the result of cultivation, one of those things that made man such a dominant species and you’d be right.

Picking out rare mutant plants that are better to eat and selectively growing them will eventually lead to a crop that’d never exist in the wild as a whole crop. Over time we’ve made rare (and generally, weak) plants common through selectively cultivating and nurturing them. We’ve gradually changed them to be increasingly different to their wild cousins. Essentially, we’ve evolved crops to suit ourselves.

This approach doesn’t have a lot of smarts: it relies on chance throwing up useful variants. (It’s not a bad illustration of how little “smarts” are needed for evolution to work though.)

A smarter way is to bred plants for particular traits by exploiting the rules of genetics, “crossing” plants to try bring certain traits or mixtures of traits out. It’s slow and laborious. You get to grow large numbers of plants over several generations to try bring out a trait.

One way of speeding up the breeding process is to generate more individual plants with different genetics and hence different traits to select from.

Natural mutant plants are mostly a result of radiation from the sun. The genetic changes that occur are rare, random and happen anywhere in the genes of the plant.

Chemical mutagens applied to plant embyros or seeds can be a way of getting more of the same, quicker. Useful traits, say, a larger tomato or resistance to soil salinity, can be selected and breed. You won’t know what genes have been altered, nor how many, but that’s also true of the naturally-occuring mutants too.

Salt-tolerant wheat (source: wikipedia.)

Salt-tolerant wheat (source: wikipedia.)

There are other ways of generating new varieties, of course. A botanist or plant breeder would give me a very long list of them! They’d include hybrid techniques and growth from calluses, for example. All of these exploit altered genetics in different ways.

Most of those “natural” healthy and tasty plants down at the supermarket are the result of these approaches in one way or other. All can produce damn fine food crops and they’re OK, provided they’re tested.

That a breeding method looks “natural” isn’t a sinecure that it’ll produce a safe plant. You might breed for a better spud, but be unaware that you’ve increased the glycoalkaloid level in the tubers too. (It’s also why you know not to eat green spuds and to cook them well.)

People have learnt from mistakes, of course. If you make a new strain, better make sure you test it properly. It’s not how you make the new plant, it’s how you test it.

Selecting and breeding plants has a flaw: you might select for one trait, but the genetic changes for other traits can–and will–come “for the ride”. These hidden changes are much more complex and less well understood than those from GE. When nature tinkers, “she” can make far more radical changes than scientists do and scientists have to figure them out after the fact.

(Source: wikipedia)

(Source: wikipedia)

GE is much better at ensuring breeders don’t get unknown, untested genetic variants. A GE approach makes very specific changes that the breeder determines and only affects a small, specific, parts of the plant’s genes.

Using GE, breeders make specific changes without having to select from random variations in rare individuals or finding ways to generate more variant individual plants to select from. Breeders can create plants that would be impractical to generate using conventional breeding, but are useful. GE isn’t cheap or easy, but the initial breeding stages only have to be done once.

I imagine if you philosophically object to “blind tinkering”, I’d hear you tell me we have to use GE methods.

Either way, what makes the plant safe to eat is food safety testing, not how the plant was made.

Foods are tested to be safe for the vast majority of people. They’re tested better than they ever have been.

Our pre-historic foraging ancestors probably tested unfamiliar plants by sampling a tiny piece and waiting for a few days too! If you’re still concerned about food safety, just eat a small amount the first time.

Then stop worrying, life’s not worth that, eh?

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Metagenomics-finding organisms from their genomes

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