[Sarah]

Sarah asked the Naked Scientists:
   
Hi there,

We know that some genetically modified foods are designed to be pest-resistant, and were wondering about the mechanism.

My husband thinks that they are engineered to produce a pesticide (ie. a toxin). I think that it's more likely that the crops are engineered to produce a compound that is unpalatable to whatever insects typically eat them.

Can you settle this debate?

Many thanks!
Sarah
(Canada)

What do you think?

[myriam]

Hi there

yes you are right

In fact, engineers now can manipulate the genes of living organisms which can be transformed as  planned but the further effects of that are not always studied or well known

to give to a plant the capability to kill the insect, engineers have to do lots of work in the lab to isolate the gene producer of the toxin  and introduce it in the genome of the plant so the resulted plant  is genetically modified and hence it behaves as a pesticide

but the most important question here is "are we eating pesticides" ??

Myriam

[SeanB]

The genes to encode a pesticide ( or a protein that is like a pesticide to the particular target) is selected from a donor organism that produces it naturally. This is then placed in the recipient cell by various methods, either via a virus or by injection or by explosive recombination.

The surviving cells are then cultured and the descendants are tested to see who has the gene in the correct place more or less, and if the gene is expressed and is effective. The cell lines that pass are then grown in vitro, and the seedlings are planted and allowed to grow to maturity and produce seed. Most important ( from the perspective of the manufacturer) is to make sure the seed that the farmer gets is sterile, and does not produce a viable seed, whilst meeting most of the resistance requirements if feed with appropriate fertiliser and copious water.

[ricbritain]

Hi there

yes you are right

In fact, engineers now can manipulate the genes of living organisms which can be transformed as  planned but the further effects of that are not always studied or well known

to give to a plant the capability to kill the insect, engineers have to do lots of work in the lab to isolate the gene producer of the toxin  and introduce it in the genome of the plant so the resulted plant  is genetically modified and hence it behaves as a pesticide

but the most important question here is "are we eating pesticides" ??

Myriam

Similarly some crops are 'engineered' to withstand temperature variations or extremes. By your logic we should be asking 'are we eating anti-freeze'.

[imatfaal]

Similarly some crops are 'engineered' to withstand temperature variations or extremes. By your logic we should be asking 'are we eating anti-freeze'.

And to an extent Myriam would be right! Plants with increased cold resistance were found to have higher levels of omega3fatty acids - and transgenic plants have been created which have increased levels.  So we are in fact eating (and smoking as done originally on tobacco) natural anti-freeze.  Admittedly it's not ethylene glycol, which is nasty stuff to ingest, but it is there. Matthew

[thedoc]

Go to the podcast page.
or [chapter podcast=2580 track=10.05.16/Naked_Scientists_Show_10.05.16_6277.mp3] Listen to the Answer Now[/chapter] or [download as MP3]

[echochartruse]

Similarly some crops are 'engineered' to withstand temperature variations or extremes. By your logic we should be asking 'are we eating anti-freeze'.

Isn't anti-freeze in ice cream and other such products?