4.4—Proteins are carefully characterized
The proteins introduced into GM crops are carefully characterized
Analysis of Peer-Reviewed Research:
Smith claims that the notion that a single gene produces a single protein is outmoded. While it is true that science learned recently that through a phenomenon called alternative splicing, it is possible to produce more than one protein from a single gene, this is hardly a reason to claim that we don’t understand what is happening. First of all, in bacteria a single gene directs the synthesis of a single protein, and in higher organisms the situation is predominately the same way. What the added complexity (more than one protein from a gene) means to the biotechnologist is that they must identify the proteins that are actually produced in a new transgenic plant. There are good methods available (eg. RNA message analysis, reaction with specific antibodies, and so on) for the identification of transgenic proteins, moreover, if a plant does not produce the intended protein, it will not display the intended trait. Incorrect proteins will just not do the job the researchers wanted the transgenic protein to do. Genetic Roulette is incorrect when it asserts that the possible presence of alternative proteins is not evaluated and forgets that a plant that produces the wrong protein won’t be selected. Of course even if it were produced there is no reason to believe that an alternative protein will be a safety hazard since almost without exception proteins are safe to eat.
The claimed possible example of multiple proteins being formed by alternative splicing – namely Bt11 insect protected corn – is misrepresented by Smith. Genetic Roulette mentions that several different Bt proteins have been detected in the corn variety Bt 11, and Smith suggests that alternative splicing might be the explanation for these different proteins. To support his speculation he inaccurately claims that the different sized proteins have only been crudely characterized by weight, and that their sequences had not been determined. The Canadian government reports about this matter (Canadian Food Inspection Agency 1996) to which his reference citation refers shows that he is misleading readers. His claims about alternative splicing as an explanation are just plain wrong. Safety assurance for this corn variety has been fully substantiated by numerous regulatory agencies (Agbios (2005) Agbios GM database entry SYN-BTØ11-1 (BT11 (X4334CBR, X4734CBR)
Agbios (2005) Agbios GM database entry SYN-BTØ11-1 (BT11 (X4334CBR, X4734CBR)) www.agbios.com/dbase.php?action=Submit&evidx=18# accessed Dec 26 2008. Maize line Bt11 was developed through a specific genetic modification to be resistant to attack by European corn borer (ECB; Ostrinia nubilalis), a major insect pest of maize in agriculture. Basic safety data are provided.
Canadian Food Inspection Agency (1996). Decision Document DD96-12: Determination of Environmental Safety of Northrup King Seeds’ European Corn Borer (ECB) Resistant Corn (Zea mays L.) www.inspection.gc.ca/english/plaveg/bio/dd/dd9612e.shtml accessed Dec 26 2008. Bt 11 insect protected corn was evaluated by the Canadian Food Inspection Agency. The Bt protein is a truncated version to provide better expression in corn plants. Fragments of this protein are formed by proteolytic digestion and these have been thoroughly characterised.
Transgenes may create more than one protein
1. Genetic engineering technology was created based on the outmoded notion that a single gene will create only a single protein.
2. Due to a process called alternative splicing, a single gene can produce many different proteins.
3. Although the bacterial genes used in GM crops will not, in their natural state, be alternatively spliced, scientists modify the sequence in a way that may facilitate this.
Genetic Roulette claims that GM crops may actually have the wrong protein in them.