In this series I'm reading and briefly reporting on each of the "600 studies" held on the GENERA database, published at Bifortified.org, in the order in which they were listed on 18 Sept 2013. The general purpose is to counter the extraordinary claims that the entries on this list demonstrate the human food safety of GM crops. See the Introduction to this series [link].
My Great Big List of Studies: Entry 11 – Álvarez-Alfageme et al 2011 [pdf link]
This environmental study on experimental GM research lines (wheat with increased resistance to powdery mildew) didn't investigate any aspect of human food safety of existing GM crops, but it is in an interesting series with important precautionary notes.
The authors declared that the funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. They also declared they had no competing interests.
We don't normally hear about the difficulties and failures in the path to developing a single commercial GM crop line. GM companies generally present data about their commercial crop to regulators as a fait accompli, and the false narrative chosen by the GM PR operatives is of a little gene from a benign species carefully snipped and pasted into a new crop to produce one new protein with useful traits.
But through this particular GM development we have been given a few rare insights into the problems of GM development techniques and the unconscionable and unevaluable range of risks they pose.
At the time of writing this study the authors were fully aware of the multiple unintended effects that the intended engineering of one simple protein could produce. They referred to an earlier field trial of a number of their GM wheat plants Zeller et al (2010) [pdf link]
that waved a flag in the face of most regulatory decisions.
- "Our results demonstrate that, depending on the insertion event, a particular transgene can have large effects on the entire phenotype of a plant and that these effects can sometimes be reversed when plants are moved from the glasshouse to the field. However, it remains unclear which mechanisms underlie these effects and how they may affect concepts in molecular plant breeding and plant evolutionary ecology.
Three of the four lines trialled produced wildly different results when grown out in the field, to the extent that the yields from two of the lines halved. One little protein engineered into a crop could have profound plant-wide effects. While changes in such measurable variables as yield can be readily identified, with such plants screened and excluded, it is the unmeasured/able invisible changes that may occur within a plant that are of concern for human health and environmental safety.
Álvarez-Alfageme et al noted concerns about the unintended effects of GM crops on non-target insects in the field, saying in their introduction that
- "Such unintended effects could be caused
(i) directly, by the expression products of the inserted genes,
(ii) by pleiotrophic effects of the transgene expression, or
(iii) by the transgene integration into the plant genome."
Noting that these GM transformations "should not increase problems with insect pests" they nonetheless entered an investigation.
They reported several findings in their study – some of the GM wheat lines did better than others, and they noted no significant differences in populations of two of the three wheat pests investigated. However they reported a significant finding in respect of aphids...
- "In the convertible glasshouse, aphid abundance was negatively correlated with powdery mildew occurrence, and resistant [GM] plants harboured larger aphid populations than their susceptible controls."
That is, the most effective GM plants repressed powdery mildew, but suffered increased attack from aphids. The authors were not able to offer a definitive explanation and proposed further study to test various hypotheses. In contrast the authors reported non-significant results out in the field, suggesting this may have been because the fungal pressures had not been as high.
It's very refreshing to read these sorts of thoughtful and honest studies in GM crop development that directly open up the shortcomings of these development techniques to other scientists and the reading public.
I'd meant to note that the control lines were described by the authors as 'negative segregants'. I understand this to mean that these are offspring of the GM plants but without the specific transgenes of interest. For regulatory assessment purposes these should be regarded as inappropriate controls, since they are themselves products of genetic transformation and subject to unintended effects, regardless of whether they contain the specific transgenes.