Re Agronomists assertion that "the viral family that is responsible for oncogene-based cancers are the retroviruses.. that.. [contain] RNA". and "Then you might be able to tell a dumb agronomist like me how a DNA sequence can do this"
Agronomist is completely wrong. For example, the human papilloma virus that causes cervical cancer is a DNA virus. And there is no debate about whether this virus causes cancer of not. The association has been so well studied and established that we now have a vaccine against this virus and the Australian responsible for it has won a swathe of awards for its development. Perhaps this "dumb agronomist" would like to read the medical and scientific literature on the subject?

Re cancer claim: Agronomist is right (and this is exactly the problem regarding the possibility of causing cancer) - human cells contain oncogene sequences, and these cells have the ability to be transformed into cancerous cells.

Re DNA jumping species: GM DNA has already jumped species. The whole process of making GM crops is that of making genes jump species. Of making DNA from viruses, bacteria, plants and animals go into the genome of crops and other organisms where they would never normally be found.

Re DNA matches and "if this was strictly correct, then GM plants wouldn't exist".
The process of genetic engineering is that of putting DNA sequences into plants and other organisms without needing these matching sequences in the recipient DNA..

Re comments about low grade foreign DNA - That's like saying that those who were able to tolerate tobacco, asbestos, arsenic, UV light exposure (skin cancers), malaria, tuberculosis etc would have also been selected millennia ago. In some cases, there has been some selection pressure. But these things still kill millions every year. You should also note that selection pressures only work if there is selection before the age that people reproduce. Most cancers hit after people have reproduced.

Re the questions around: "Why is it only when attached to the Roundup Ready gene is the CaMV promoter likely to be dangerous?"
There are two overlapping issues here. The first is the total level of exposure to the viral promotor sequence. The second is the nature of that exposure. For the first issue, cauliflower mosaic virus infects only certain plants naturally, humans don't eat these plants as a large proportion of their diet (compared say to wheat) and these plants become diseased and unpleasant to eat. Diseased plants are unlikely to make it onto supermarket shelves in significant numbers. Therefore, humans naturally have a low exposure to the virus. In contrast, in GM crops, the promotor sequence is present in every cell of the plant and in a great number of different types of crops that are much more regularly eaten, making the total exposure to the promotor sequence much greater than ever before. The second issue is the nature of that exposure. In nature, the cauliflower mosaic virus rarely if ever infects the DNA of the plant. It remains attached to its other normal viral genes and, if it is not in the nucleus, is encased in a viral protein coat that is resistant to digestion (see http://www.i-sis.org.uk/eatingcamv-pr.php). In contrast, in GM crops, the promotor seqence has been removed from its normal companion genes and from its protein coat and placed directly into the genome of the plant next to DNA that would normally be foreign to it. There is good evidence that in this form, the CaMV promotor sequence acts as a recombination "hot spot" with the ability to move around the genome and take other bits of DNA with it.

A few issues to consider.

1. The human papilloma virus carries its own oncogenes, two of them in fact. The proteins produced bind to genes that manage cell growth and repair cell damage. The mechanism is very different to retroviral-induced oncogenesis. The CaMV 35S promoter has no oncogenes. http://www.medinstitute.org/includes/downloads/hpv_report.pdf?PHPSESSID=fa5c3fc5e02a01bf6790353aab9a253a

2. Recombination. Detail the evidence that CaMV acts as a recombinant hotspot. Who says so? What have they compared it with? What experiments were conducted? What was the increased frequency of recombination? There was nothing in the article you pointed to on this. In fact the article seemed to suggest that the evidence so far indicated the CaMV 35S promoter was not a major hotspot. I quote: “Wintermantel and Schoelz (1996) found that recombination was observable in every plant when virus invaded transgenic plants with CaMV genes inserted on plant chromosome. They believed that most observed recombination occurred in the cytoplasm during reverse transcription and that there was little chance for recombination between invading virus and CaMV transgenes on the chromosome.”

3. Making GM crops. When Agrobacterium infection is used to transfer genes, a plasmid is involved. This is a bit of circular DNA containing the construct to be introduced and special flanking regions. These special flanking regions in effect trick the plant into incorporating DNA into its chromosome when it would not normally do so. The flanking regions are lost in the process. Transposons use a similar process http://waynesword.palomar.edu/transpos.htm. As the flanking regions are lost, the only way the genetic material can be incorporated into another genome is via recombination with similar sequences.

4. Before the 20th Century we didn’t have supermarkets. For the best part of 10,000 years before that we were eating vegetables that were infected with CaMV. Each cell infected with CaMV might have thousands of viral genomes and hence thousands of copies of the 35S promoter. There are 191 known host plants in 40 families (http://www.grodan.dk/sw18601.asp, http://image.fs.uidaho.edu/vide/descr267.htm) including tomato, pepper, cucumber, melons, squash, spinach, celery, beets, and petunia. Granted we don’t normally eat petunias, but the rest are common parts of our diet.

The last posts from me were direct quotes from an expert in this field and I will post their response when they get back to me.
My comment to the health debate from both sides is ...
Consumers aren't interested in the scientific details or theories, they just want to know it is safe for them and for their offspring.
Why not support the independent health tests to prove if GM food is safe or unsafe?

Comment from Charles Benbrook on how precise GM is
http://www.precaution.org/lib/06/benbrook_interview.060304.htm

In fact it's fundamentally more imprecise, in that the techniques that are used to move the trans-gene into the crop are no more precise than a shotgun. They shoot into the cells thousands of particles that have the trans-gene coating and hope that one penetrates into the inside of the cell and gets picked up and stably expressed. They hope that it's only one, and that it gets expressed properly. But they have no way of knowing whether it does, and in fact they do know that it's likely that more than one of those particles actually leads to some expression, and some may lead to some partial expression.

So they have no control over where in that cell or where in that plant's genome the new genetic material gets lodged and expressed. Because they don't have control over that, they have absolutely no basis to predict how that trans-gene, the new genetic material, is going to behave in the future as that plant deals with stresses in its environment, whether it's drought, too much water, pest pressures, imbalances in the soil, or any other source of stress. They just don't know how it's going to behave. They don't know how stable that expression is going to be, or whether the third generation of the plant is going to behave just like other generations. They don't know whether the promoter gene, which has been moved into the plant to turn on the new piece of genetic material, will influence some other biosynthetic pathway that's in the plant, turning on some natural process of the plant when it shouldn't be turned on, or turning it off too soon. There are all sorts of things that they don't know.

So Charles Benbrook is your expert. Charles Benbrook is an agricultural economist, former agricultural policy lobbyist and PR consultant to the organic industry http://www.organic-center.org/about.staff.php?action=detail&bios_id=43.

Which of his various positions makes him an expert on the insertion of genes by genetic engineering? His position as cheif scientist for the Organic Centre I suppose?

It is interesting the way that you refuse to believe anything anybody with even the remotest links with the biotechnology industry has to say, but you swallow hook, line and sinker everything the organic lobby has to say. The organic lobby is using the GM debate as a way of falsely frigthening people about their food so they will buy more organic produce, thereby lining the pockets of those in the organic industry. Yet you hold these people up as paragons of virtue and scientists from organisations like CSIRO - who only draw their salary and most have nothing to personally gain from their research - as paraiahs. It is a strange world you live in.