Anti-Biotech Morons

[Shane Costello]

Originally posted by athon:
Ok, but if a sequence is conserved across two species, why would you transfer it? If it doesn't exist in one species, and you wish to place a coding sequence into a crop that does not possess it, how can you initially be certain that it does not have a different effect?

Well the gene may be active in one species but inactive in another, the difference being in the activity of regulaory elements. Initially you wouldn't be certain that it wouldn't have a different effect, hence the reason for field trials and a regulatory framework. At the risk of sounding like a broken record this should actually an argument in favour of GM. Conventional breeding involves the transfer of entire genomes, while GM involves the transfer of no more than a few genes. The potential for "different effects" is far greater with conventional breeding.

As for non-coding sequences, we are only just beginning to understand how complicated that issue is. Granted, it has not been attempted yet in commercial GM (to my knowledge, but I could be shown wrong), but the temptation will surely arise to use an amplifier sequence or play with promoter regions to increase yields. At the moment it is rather crude manipulation of coding sequences that produce extra growth.

I believe it's already being done. I'll have to do a bit of googling but I worked with transgenic apple plants for a while. These had been transformed with a phytohormone gene with a bacterial promoter, with the ultimate effect of prolonging shelf life.

It is definately not a simple 'take gene A from species A and it will do the same thing next to gene B in species B'. Initially the industry thought it would, and with early GM in bacteria it was as simple as that. But eukaryotic organisms are proving to have a lot of tricks to get past.

I think it depends on the specific gene and the trait it influences. Some traits are complex, and influenced by a number of genes, other traits are simple and influenced by the expression of single genes. It's not true to say that early GM in bacteria was simple. Horizontal gene transfer of genes between bacteria is a natural phenomenon, so splicing bacterial genes in bacterial genomes is an easy process in vitro. However in the case of human insulin the human insulin gene (eukaryote) was spliced into an E.coli strain (prokaryote). This is not an easy process, since prokaryotic genomes lack the promoter sequences required by eukaryotic genes.

 

[athon]

Well the gene may be active in one species but inactive in another, the difference being in the activity of regulaory elements. Initially you wouldn't be certain that it wouldn't have a different effect, hence the reason for field trials and a regulatory framework. At the risk of sounding like a broken record this should actually an argument in favour of GM.

That was my initial point (I hope we're not arguing the same thing from two different angles here...I hate that ). GM can provide enormous benefits, but only when nasty surprises have been accounted for.

Conventional breeding involves the transfer of entire genomes, while GM involves the transfer of no more than a few genes. The potential for "different effects" is far greater with conventional breeding.

You've said this a couple of times, and it's one thing I don't quite agree with. Conventional breeding requires two similar genomes to coordinate in the process of fertilisation to produce a viable zygote. You are not 'inserting' an entire genome into a sequence, but rather providing the required other half of a genome needed for a full 2n organism to exist. I think I know what you're saying, however. But I don't agree that there is a greater potential for unwanted effects, unless you account for an unexpected mutation (which has not been specifically induced, c.f. GE). But even then, this argument would be difficult to prove on either of our sides without ample evidence, which I don't think exists.

I'll have to do a bit of googling but I worked with transgenic apple plants for a while. These had been transformed with a phytohormone gene with a bacterial promoter, with the ultimate effect of prolonging shelf life.

Yeah, I've encountered the same with banana transgenics. But that was never commercialised, and I haven't come across anything else that has gotten onto the market. But, it's a matter of time.

It's not true to say that early GM in bacteria was simple. Horizontal gene transfer of genes between bacteria is a natural phenomenon, so splicing bacterial genes in bacterial genomes is an easy process in vitro. However in the case of human insulin the human insulin gene (eukaryote) was spliced into an E.coli strain (prokaryote). This is not an easy process, since prokaryotic genomes lack the promoter sequences required by eukaryotic genes.

Sorry, that was badly written on my behalf. I was meaning bacterial GE was relatively simpler, when compared with modern efforts. It was still seen as being something like playing with lego, and while today we look back and see early efforts might have seemed like it, these days we see complicated cascade effects which make the game a little trickier.

Athon

 

[Shane Costello]

Originally posted by athon:
That was my initial point (I hope we're not arguing the same thing from two different angles here...I hate that ). GM can provide enormous benefits, but only when nasty surprises have been accounted for.

So how is GM intrinsically different from conventional breeding in this respect?

Conventional breeding requires two similar genomes to coordinate in the process of fertilisation to produce a viable zygote. You are not 'inserting' an entire genome into a sequence, but rather providing the required other half of a genome needed for a full 2n organism to exist. I think I know what you're saying, however. But I don't agree that there is a greater potential for unwanted effects, unless you account for an unexpected mutation (which has not been specifically induced, c.f. GE). But even then, this argument would be difficult to prove on either of our sides without ample evidence, which I don't think exists.

You haven't been reading my links! Go back to where I gave a link on the development of wheat. Plants do not obey the diploid (2n) rule. Plants can be triploid (3n) and tetraploid (4n). The development of modern bread wheat involved an increase of ploidy, that is the acquisition of an entire genome.

Sorry, that was badly written on my behalf. I was meaning bacterial GE was relatively simpler, when compared with modern efforts. It was still seen as being something like playing with lego, and while today we look back and see early efforts might have seemed like it, these days we see complicated cascade effects which make the game a little trickier.

Transforming eukaryotic plant genomes with eukaryotic genes is a lot simpler than transforming eukaryotic genes into prokaryotic genes.

 

[Eos of the Eons]

One point of the anti-GMO crowd that hasn't been mentioned is laws which allow GMO foods to be sold without labelling referring to their modifications. If one were allergic to fish, then knowing that salmon genes were transferred to a tomato would be useful information. I understand that the chance of this specific transferred DNA creating proteins that would trigger allergic reactions is very, very small, but it is not zero.

I haven't seen this addressed much.

You have to look at what the gene codes for. If the gene makes the skin tougher with fish dna, then there is no chance whatsoever that a person who is allergic to fish has to worry about. It is now a tomato gene expressed in a tomato with all the tomato properties.

Knowing a fish gene is now in a tomato would hopefully show how it doesn't affect people who are allergic to fish when they eat it.
But we all know there will be people who will be scared. Unduly.

Look at it this way. Say they put a cat gene in a dog to make the dog's fur the color the cat's was.

I would have no qualms touching the dog even though I'm allergic to cats. It is dog fur still, grown by a dog.

That sequence of genes is now the dog's sequence of genes. All genes are the same whether you are a bacterium or a tree or a slug, or a bug, or a blade of grass, or a human.

Adding one little trait to something else is not enough of a change to make it so much like the dna donor that a person will react to it they way they do to the donor.

A half dog, half cat I would be worried about. You can't do that though, unless you have all the time in the world to change that many genes manually and still make it work to make a whole dog/cat.

 

[Eos of the Eons]

This is not an easy process, since prokaryotic genomes lack the promoter sequences required by eukaryotic genes.

I don't think most people have a clue how complex genetics is. This is one example. Who the heck is going to know what a "promoter sequence is?"

Suffice it to say that the GM scientists actually are extremely educated and really do know what they are doing.

 

[athon]

Transforming eukaryotic plant genomes with eukaryotic genes is a lot simpler than transforming eukaryotic genes into prokaryotic genes.

Sorry, just one interesting point I thought of while reading this.

You're obviously somebody who works in the field of GE (or at least something that involves molecular biology) now, right? And you're seeing it as a rather straight-forward science where most interactions can be foreseen in spite of the fact that recent advances have, if anything, shown us that the field is much more complicated than we used to think.

Myself, I was in the field about seven years ago, when there was an air of 'the concept is simple enough'. We knew about non-coding sequences, and suspected how they worked, but had little grasp of just how far-reaching many of the interactions went.

It seems a little ironic that I'm arguing that we should tread lightly, and you're suggesting the games of GE has always been played, so we have less to worry about than everybody makes out.

Anyway, I did read your links on plant genome exchange (sorry -- I didn't have time earlier, and should have said as such. Come teach a few of my classes -- that should free some time. haha), and I do see your point.

But I interpreted it differently to you. If an entire genome is accepted, there is an increased chance that the organism will not function due to incompatiblities (more genes that can negate effects etc.). That's why it is so rare in nature. Just inserting one gene will increase the chance the organism could still remain viable, but there is also the increased chance that it will create effects in areas separate from is anticipated, whilst still enabling the organism to survive.

I'm still strong in my belief that we should remain aware that genetics is a complicated field. And when the genie is out of the bottle, breeding in the fields, it's too late after a few years to say 'Hell, we didn't expect the genie to do that'.

Athon

 

[The Don]

A half dog, half cat I would be worried about. You can't do that though, unless you have all the time in the world to change that many genes manually and still make it work to make a whole dog/cat.

I believe the correct term for such an animal is actually a CatDog

 

[Shane Costello]

Originally posted by athon:
You're obviously somebody who works in the field of GE (or at least something that involves molecular biology) now, right? And you're seeing it as a rather straight-forward science where most interactions can be foreseen in spite of the fact that recent advances have, if anything, shown us that the field is much more complicated than we used to think.

You're in danger of erecting an unintended strawman. I agree with everything you say, but I don't see how it's pertinent to GM, but somehow irrelevant to conventional breeding.

But I interpreted it differently to you. If an entire genome is accepted, there is an increased chance that the organism will not function due to incompatiblities (more genes that can negate effects etc.). That's why it is so rare in nature.

It appears to be a fairly common occurence in plants, nor does an increase in ploidy seem to have any effect on plant vigour. Bread wheat has lasted the course fairly well.

Just inserting one gene will increase the chance the organism could still remain viable, but there is also the increased chance that it will create effects in areas separate from is anticipated, whilst still enabling the organism to survive.

Allow me to summarise your argument If I may. You appear to be arguing that the process of transforming a genome with a novel gene would disrupt the genetic sequence of said genome, possibly having far reaching effects. My point is that recombination already occurs as part of the normal cell cycle at meiosis. The potential for genomic disruption is ever present, and indeed cancer is one of the most visible results of that.

I'm still strong in my belief that we should remain aware that genetics is a complicated field. And when the genie is out of the bottle, breeding in the fields, it's too late after a few years to say 'Hell, we didn't expect the genie to do that'.

In which case it's misguided to focus solely on GM. Conventional breeding is governed by the same complicated field of genetics. A link I provided earlier pointed out that if the regulations governing GM were applied to conventional food, quite a lot of what we regularly eat would be deemed unfit for huma consumption. Don't worry, the genie is under very close scrutiny.

 

[Eos of the Eons]

I believe the correct term for such an animal is actually a CatDog

I've always wondered how they get rid of their waste products? I don't see any type of anus or anything!