h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

For the sake of simplicity, let's talk about plant breeding:

I often hear people saying that genetic engineering has been happening forever (by nature, and by people pre 1900s). But aren't there significant differences between species development via natural pollination, human acceleration of that process by manually crossing plants, and removal of gene material in a lab and putting it in an unrelated species?

One main difference is that in nature only closely related species will cross breed to produce new species eg you don't get a pear tree crossing with a potato.

And I had thought that was true also for low tech plant breeding by humans.

And that modern genetics was allowing crossing of plants that wouldn't happen in nature otherwise.

Plus there is a mixing of genetic material from similar plants that wouldn't happen in nature, or at least would happen very slowly over many generations).

Is that true, or am I missing something?

That's pretty much true. The reason people don't like gene splicing has nothing to do with any real danger and everything to do with postmodern rejection of the idea that science can be a force for good coupled with some mystical mumbo jumbo about how 'Nature knows best' and 'We shouldn't play God'; to these people, the difference between natural and evil artificial techniques seems to be the amount of control the scientist has over individual genes and molecules.

DNA sequences are very analogous to a computer program. They're instructions that a cell's machinery carries out. Modern genetic engineering is then just a more deliberate re-writing of this code. Evolution could then be described a slow, limited re-writing of the code.

I don't like gene splicing because I'm a computer programmer. Gene splicing is like changing a random byte in the middle of a program and then observing what the program does to see what the effect of the change was. I know from experience that it can throw up some very unpredictable behaviour.

Those are both helpful analogies, thanks.

I agree that it is like that Gnomon, but not completely like that. There is some knowledge of the function of the genes being changed/replaced, and the purpoted function of the replacement genes. But it isn't much.

Well it should be fine just so long as the DNA is object-orientated .

The is one main reason to be against GM products and that because they are made by companies such as Monsanto, (the patriotic corporation that gave the world Agent Orange), modify the crops not for higher yields, greater resistance to drought or pests, but to the pesticides that Monsanto are in the business of selling and patenting the new strains so people can't store seeds because they belong to the corporation. But, remeber corporations are persons and we shouldn't judge their psycopathic ways.

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I thought natural evolution was a bit like that too.

Noggin

That's what I was thinking too Nog.

So - what's the difference?

I don't think there is a difference. Man-made genetic engineering is just much much quicker. But remember that natural evolution can throw up some pretty bloody nasty things too (think MRSA, HIV, Noel Edmonds etc). So if we can do that very quickly (and I am a genetic engineer!), we have to control what we create equally as carefully. And that isn't easy.

That's largely true yes.

However viruses are lifelike things that can and do insert their DNA and any DNA they have attached to them into a hosts chromosome, they then hijack the cell's replication systems to make many copies of themselves and make more viruses to carry on doing this some more.

Viruses are very capable of naturally inserting foreign DNA into cells and have been doing so for billions of years. So what we are doing is not necessarily as unusual as some might think.

This is one of the reasons that viruses can be a pretty major cause of cancer. It is also exploitable - and viral vectors are often used to introduce DNA of our choice into foreign cells. They are used to *do* the genetic engineering.

I dunno how that happened but I thought there was only a post 1 when I wrote that.

That's not quite what gene splicing is when sticking it into other species that will go into the public domain. The geneticists know what the bit of DNA will do. It is not a random byte but a known sub-routine that is being added. That's why sticking some fish DNA in a tomato doesn't make a tomato fishy or smell fishy etc it just gives the tomato the characteristics of the fish which particular subroutine coded into that DNA gave to the fish.