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Tuesday, September 11, 2012

independently funded articles on GM potatoes

http://www.biofortified.org/genera/studies-for-genera/independent-funding/ is a list of 126 articles on GM foods, apparently independently funded. 10 contain potato in the title.

Only two involved feeding potatoes to animals:

Ewen SWB, Pusztai A (1999) concluded that it made the rats sick. 

Rhee, G.S., Cho, D.H., Won, Y.H., Seok, J.H., Kim, S.S., Kwack, S.J., Lee, R.D., Chae, S.Y., Kim, J.W., Lee, B.M., Park, K.L., Choi, K.S., 2005.  concluded that the rats were fine.   I could not find the complete article

Kuiper HA, Hub P J M Noteborn, and ACM Peijnenburg. 1999 Adequacy of methods for testing the safety of genetically modified foods. Lancet 354:1315-6. This paper suggests  Arpad Pusztai's research was flawed.

I can't find this on the internet but would be interested to read it. 

http://www.ncbi.nlm.nih.gov/sites/pubmed/18320254  assesses the bioavailability of carotenoids in GM potatoes, and involves subjects eating 1100g of potatoes on two occasions a week apart. This may have been enough to assess its bioavailability but it does nothing to assess its safety as a food.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1242293/?tool=pubmed  describes mass spectrophotometer fingerprinting of GM and non GM potatoes but does not include any feeding trials.

Defernez M, Gunning YM, Parr AJ, Shepherd LV, Davies HV, Colquhoun IJ. (2004) J Agric Food Chem. 2004 Oct 6;52(20):6075-85. NMR and HPLC-UV profiling of potatoes with genetic modifications to metabolic pathways. describes differences in metabolites in various GM and non GM cultivars. It finds differences but said they did not appear important, again no testing on animals.

Enot DP Manfred Beckmann, David Overy, and John Draper (2006) Predicting interpretability of metabolome models based on behavior, putative identity, and biological relevance of explanatory signals PNAS October 3, 2006 vol. 103(40): 14865–14870 How to work out whether plants have substantially equivalent metabolite content, including an analysis of transgenic potatoes. another metabolite fingerprinting exercise, without actually testing any of the potatoes on animals or humans.

Next is: Lehesranta,Satu J., Howard V. Davies, Louise V.T. Shepherd, Naoise Nunan, Jim W. McNicol, Seppo Auriola, Kaisa M. Koistinen, Soile Suomalainen, Harri I. Kokko and Sirpa O. Kärenlampi. 2005. Comparison of Tuber Proteomes of Potato Varieties, Landraces, and Geneticallyn Modified Lines. Plant Physiology 138:1690-1699.

it has a lot of information about proteomes and the differences between varieties both GM and other wise but no conclusions about how safe they are to eat. 

The eighth is Rhee, G.S., Cho, D.H., Won, Y.H., Seok, J.H., Kim, S.S., Kwack, S.J., Lee, R.D., Chae, S.Y., Kim, J.W., Lee, B.M., Park, K.L., Choi, K.S., 2005. Multigeneration reproductive and developmental toxicity study of bar gene inserted into genetically modified potato on rats. J. Toxicol. Environ. Health A 68, 2263–2276. 

This paper concluded that the GM potatoes didn't do the rats any harm, but I cannot find the complete paper only the abstract.

Shepherd LV, McNicol JW, Razzo R, Taylor MA, Davies HV (2006). Assessing the potential for unintended effects in genetically modified potatoes perturbed in metabolic and developmental processes. Targeted analysis of key nutrients and anti-nutrients. Transgenic Res. 15(4):409-25. Again I could only find the abstract and it did not refer to the safety or otherwise of eating GM potatoes.


Why I don't want Teagasc's GM potato trial to go ahead

At their research facility Oakpark, Teagasc have inserted a Late Blight phytophthera infestans resistance gene into Desiree potatoes and have been growing them in green houses. They now have  permission to trial them outdoors. This blog outlines why I don't want this to happen.
Potato flower showing yellow stamens which produce pollen, surrounding
the green stigma which accepts it, for fertilization of the eggs below.

GM plants are  different to normal ones due to the method of insertion of the GM genes. During normal reproductive behavior, plants arrange their genes, in a specific way. When a gene is inserted by a living vector or a gene gun, there is no control over where the gene is inserted into the chromosome and so it may cause unpredictable changes in the genetics of the plant.  It may change the expression of existing genes, tuning them on or off, it may scramble others, and it may cause the production of new proteins.

Potato berries look like their relative, the tomato. They contain true potato seed (TPS)
Arpad Pusztai who worked in the Rowlett Research Institute, in Scotland, tested GM potatoes, into which a snowdrop lectin gene had been inserted. He fed them to rats, as part of a mixed diet, using unmodified potatoes as a control and also feeding a group of rats on the unmodified potatoes injected with lectin. He reported health issues in the rats eating the GM potatoes but not in the other two groups attributing the problems to the modification process.  Pusztai's and Ewan's peer reviewed results were published in the Lancet in 1999.  There is a good pod cast of Arpad Pusztai being interviewed here  

The potato that Teagasc is working with is the domestic cultivar Desiree, Solanum tuberosum into which they have introduced a gene from a closely related, but different species, Solanum venturii. Because these two species are capable of hybridising naturally they are calling it cysgenic rather than transgenic. What this means is that the gene could be introduced by traditional plant breeding methods. However, it would take longer to breed a commercial cultivar as the progeny would have many of the traits of the wild venturii species, and would have to be back crossed to the domestic potato for several generations to improve it. Desiree is a prolific producer of pollen and seeds. The trial will no doubt be carried out very carefully to ensure that there is no genetic drift from the trial to other potato crops however the GM genes could be transferred several miles by pollen on insects, and the seeds could be transferred by machinery or by people deliberately taking them to grow out themselves.

Members of the potato family, also known as the Night shade, or Solanaceae family contain many poisonous substances.  Potatoes leaves and fruit are poisonous and although potato tubers contain only small amounts of glycosides this can easily change if they are left in the light. It is possible that the GM process could cause the production of some new poison in potatoes either brought from the venturii species or caused by mutations and genetic disruption around the site of the inserted gene. It seems Teagasc have no plans to test for toxicity in the GM potatoes.

The trialling of GM products on animals to assess their safety has largely given results showing that the animals didn't suffer. Some are reviewed here. Of the 42 reviewed here, only two showed negative results. However both were in potatoes. One of the worrying things about modern scientific research is how much of it is funded by industry. The fact that Puzstai's contract was not renewed after he found problems with GM potatoes,  and said on television that he wouldn't like to eat them, (he was working for the British government) makes me wonder who would fund unbiased research, or allow publication of negative results.

Contamination of Non GM crops is inevitable once they are released to the public. In their own trial Teagasc showed that Desiree pollen travelled over 20m, carried by a beetle. They did this by planting Desiree potatoes surrounded by Golden wonder potatoes. As Golden Wonder potatoes are male sterile they do not produce berries unless they receive pollen from another cultivar. They found a small amount of viable seed on the Golden wonder potatoes, more than 20 away from the Desiree potatoes.

Seedlings from true potato seed do not all germinate in the second year. Unless great care is taken seedlings and their tubers could contaminate other potatoes. They might look identical to the original Desiree and could only be found using expensive tests. If Teagasc had chosen a male sterile variety such as Golden the risk would be considerably reduced.  If released this GM potato could cause invisible contamination of visually similar, non GM potato varieties.

Potato seedlings emerging under beans, in
my garden, two years after potatoes were grown there

On their website Teagasc refer to the fact that cysgenisis is being considered for exclusion from the scope of GMO legislation, by the European Commission. This would mean that  no license would need to be applied for for GM crops where the inserted genes were from a close relative.

Another piece of information on Teagasc's website is the fact that BASF has applied to the European Food Safety Authority for a license to market a GM late blight resisitant potato  and another GMO potato 'Amflora' has already been licensed. Amflora was developed for industrial starch production and not for human consumption. If the GM blight resistant cultivar were introduced here, it would be easier to introduce the industrial varieties and other GM crop species. Once GM crops have been introduced to Irish farms it will be impossible to prevent genetic drift into non GM varieties. It will be particularly difficult to control if wind pollinated crops such as sugar beet and maize are introduced. Bee pollinated rape seed will also be impossible to contain as it will become a roadside weed as it is in North America. This will compromise organic farming, which prohibits the use of GM crops. 

The apparent ease with which blight resistance can be introduced to potatoes is very attractive. Late Blight has become an increasing problem,  since it began to reproduce sexually in Europe.  The potato is the best producer of food per acre in terms of calories that we can grow in this climate. New potato cultivars are loosing their resistance quickly as the blight organism evolves. However introducing one gene by genetic engineering is unlikely to produce a lasting resistance. It is by growing genetically diverse strains of potatoes in a landscape of different crop species, that the best protection from evolving blight and other diseases is most likely to be found, in other words in genetic biodiversity. 

Breeding potatoes for blight resistance using traditional plant breeding methods is quite successful. Some of the most resistant varieties, that have cropped well here inspite of four bad summers in a row have come from Sarvri Trust. The Sarvri family have been breeding blight resistant potatoes, in Hungary for over 40 years, using traditional plant breeding methods, to transfer blight resistant genes from wild potato species to the domestic type. The Sarvari trust in Wales took up the work of the Sarvari family in 2002, preparing selected cultivars for commercialisation. Many of us have been growing Sarpo potatoes for years and have appreciated their blight resistance during the recent bad summers.  The future of the trust is now in doubt and its director David Shaw said at its open day that as little as £100,000 could make all the difference. You can listen to an interview with David Shaw here

In Ireland the organisation Spuds is organising trials of Sarvari Trust potatoes by volunteers. Here Nike Ruf is interviewed about the project. 

The consolidation of the seed industry is shown diagrammatically below. Three major chemical companies own or control most of the seed companies. This consolidation has happened in the last 40 years or so and has gone hand in hand with the reduction in available crop varieties. The introduction of  regulations for seed production, originally inteded to protect farmers form badly behaved seed companies now threatens agricultural biodiversity. As the seed industry consolidates the number of available varieties of seeds is reduced, especially  varieties that perform well without chemical inputs.