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Forest Biotechnology: Drawbacks and Myths

Neil Carman
Sierra Club

Forest biotechnology raises concerns because certain areas such as genetic engineering pose serious challenges to natural forest ecosystems compared to classical breeding methods. Genomics also suggests the need for deeper insights into understanding DNA as part of cellular living systems than presently exist. Genetically engineered (GE) trees pose risks unlike most annual GE crops, since trees are long-lived organisms capable of producing large volumes of pollen and seeds allowing escape from confinement.

The vast majority of GE research and likely applications in forestry to date have been with tree plantations.  Tree plantations are highly simplified agroecosystems that are poor substitutes for natural ecosystems and their biodiversity. Tree plantations are often associated with negative environmental and social impacts: reduced water resources, rapid deterioration of soils, loss of biological diversity, and the encroachment and eviction of indigenous peoples. Are we opening a Pandora’s Box of lab-created life forms that once released into nature can not be recalled?

What is Genetic Engineering?

Genetic engineering is a radical new technology using crude, imprecise methods for cutting and pasting genes together in a laboratory to create new life forms that will have unintended consequences due to our inadequate understanding of genetics. One definition of genetic engineering: “The use of new and revolutionary laboratory techniques, representing a synthesis of molecular genetics, biochemistry and microbiology, to modify the genetic makeup of cells and organisms through the manipulation of individual genes.” (Suzuki 1990).   Genetic engineering often refers to artificially splicing new traits into the genetic code of organisms, typically by transferring genes from one or more species into unrelated organisms, termed transgenics (Suzuki 1990).

Transgenic technologies allow transfer of DNA in ways that do not occur in nature, not only between species, but even from bacteria to trees or animals to plants (Suzuki 1990). By casting aside the age-old species barrier, scientists can produce a new array of unstable life forms in the laboratory, since typically thousands of experiments are required to produce one successful insertion. The great attraction of genetically engineered life for corporations is that it can be genetically identified and patented. A life patent will include rights over subsequent generations, too.

Francis Crick and James Watson first unraveled the molecular structure of the DNA double helix in 1953, and two decades later the first signs of genetic engineering in laboratory manipulation of the DNA code began to appear (Watson 1987). But genetic engineering is turning out to be far more complex than previously thought and cracks in its foundation reveal a need for new theories about how living systems operate at the molecular level. In 2002, Barry Commoner published an article entitled “Unraveling the DNA Myth: The spurious foundation of genetic engineering” presenting a review article refuting a well accepted theory of Crick’s called the “Central Dogma of Molecular Biology,” because emerging evidence had completely undermined the theory that one gene will produce only one protein. Commoner declared the “Central Dogma” dead. Commoner had previously critiqued the theory of the “Central Dogma” as long as four decades ago (Commoner 1968).

Genetic engineering is built on a simple assumption: that an organism’s genome (its entire cluster of genes or DNA) fully accounts for its block of inherited traits (Commoner 2002). In theory, a single gene (smallest whole unit of DNA code), consisting of four nucleotide sequences, produces a specific inherited trait, and the genes completely control inheritance in all forms of life (Watson 1987). In theory, DNA itself was thought to be the primary information controlling protein synthesis, and the proteins help create the cell’s internal structure and, as enzyme systems, catalyze the chemical events that produce specific inherited traits (Watson 1987).

Crick’s original theory called the “Central Dogma” suggested that a strict one-to-one relationship existed between genes and proteins: the sequence of nucleotides in a specific gene is the precise code for the amino acid sequence of a specific protein (Crick 1970; Commoner 2002). Since precisely the same four nucleotides are present in every living organism on Earth, it makes the genetic code universal (Watson 1987). Crick logically predicted that a gene should be able to produce its specific protein and specific trait no matter what species it appears in (Watson 1987).

The one gene-one protein simple assumption is why scientists continue to predict they can implant a gene for phosphorescence from a luminescent jellyfish into a monkey (Chan, 2001), or genes for bovine growth hormone into pigs (Pursel 1989), and get the predicted result, namely, the same trait in a different species. However, it doesn’t always work: the experimental monkey doesn’t glow, and the modified pigs experience far more health problems than normal pigs.

Commoner explains that such experimental problems could be viewed as the inevitable errors that characterize scientific progress; but actually this failure is far more significant, representing a significant flaw in the original assumptions of molecular biology (Commoner, 2002). The decade from 1990-2001 saw a massive scientific undertaking, a long-term test of Crick’s theory called the Human Genome Project (HGP). It is known that humans have a total of about 100,000 proteins in each individual, and by applying Crick’s theorem of one gene-one protein, the HGP predicted a similar number of genes. But the HGP only identified 30,000 human genes, revealing a huge discrepancy between the genome total and protein total. Primitive worms have about 15,000 genes or half as many as humans do, and some weedy plants have 26,000. The genes of a mouse are 99% similar to our own.

Where are the missing 70,000 human genes—70% of the human genome? If there is a one-to-one ratio of genes to proteins, there are simply not enough human genes to account for the complexity of our inherited traits, or the inherited differences between people other animals, and plants (Nature 2000). The journal Science published a possible explanation: nearly 40% of human genes are alternatively spliced. In alternative splicing, a gene’s original nucleotide sequence is split into fragments that are then recombined in different ways to encode numerous proteins, each of them different in their amino acid sequence from each other, and from the sequence that the original gene, if left intact, would encode (Science 2001).

Alternative splicing means that one gene, instead of coding for one protein, actually produces 576 variant proteins, differing in amino acid sequences (Black 1998). The fruit fly has one gene that generates up to 38,016 variant protein molecules through alternative splicing (Schmucker 2000). Clearly, no one-to-one relationship between genes and proteins exists.

Why Grow Genetically Engineered Trees?

Besides owning the patent rights to their genetic products, lumber companies wish for faster growing trees, and paper companies for trees with less lignin to remove. These industries aren’t interested in supporting a diversity of wildlife habitat and would be happy, for example, to see pine trees without all those wasteful cones for the forest creatures to eat. Such trees might also produce new insecticides on their own — just as Bt corn, engineered to produce bacterial toxins, does — and they might be herbicide resistant so competing undergrowth could be chemically eliminated.

When do We Need to be Concerned?

We’re often told commercialization of GE trees is years away, however, genetically engineered papaya trees have been yielding commercial crops since 1998 starting in Hawaii. Apple, aspen and coffee trees are also being genetically engineered, and forestry and lumber industries are investing heavily in genetically engineered Eucalyptus, pine and poplar trees.

In 2004, China became the first nation with large monoculture plantations of GE forest trees—Populus nigra engineered to produce the bacterial toxin Bacillus thuringiensis (Bt). The GE poplar plantations have been so widely planted that, according to Huoron Wang of the Chinese Academy of Sciences , “it is almost impossible to reduce the risk of gene flow from GM trees to non-GM trees…poplar trees are so widely planted in northern China that pollen and seed dispersal cannot be prevented.”(UN FAO 2005). The Nanjing Institute of Environmental Science has reported contamination of native poplars with the Bt gene is occurring (Pearce 2004).

What are the Ecological Risks to Nature?

Even the Ecological Society of America concluded that ecological risks may occur with genetically engineered organisms such as trees (Snow 2004). Take the example of a forestry company’s “ultimate tree.” A tree that no longer produces cones or seeds and eliminates undergrowth and insects is made for an industrial tree plantation but raises the specter of a silent forest, one with no more chipmunks, squirrels, or snakes on its floor, or birdsongs in its branches, and no raptors soaring above.

Companies argue they will grow their GE trees on private land, but genetic engineering can’t guarantee that a branch won’t manufacture pollen, which can blow hundreds of miles on the wind. GE trees will, inevitably, interbreed with wild relatives with unpredictable results. Faster growing trees could, for example, crowd out other species or deplete water tables. Low lignin trees might spread like the kudzu vine and become weedy pests. Pollen and seeds may spread far and wide, changing the character of our national parks and native forests forever.

Weak US Federal Regulatory Oversight

A basic concern with poor USDA oversight is many GE tree field trials are not even monitored by regulators for compliance. A review of US regulatory oversight found: “As of 2000, confinement requirements in individual tree field trials prohibited flowering, and USDA reportedly did not allow flowering of any GE trees. However, the author is aware of no current policies that prohibit flowering of forest tree field trials.”(Gurian-Sherman 2006). Serious health concerns have been documented with the weak FDA and USDA regulatory system governing GE crops (Smith 2007).

Conclusion

The complex interactions of trees, understory plants, insects, animals, fungi, bacteria and soil micro-organisms is poorly understood. At best we have an outline of the principles of interaction, but by no means do we have a complete picture. This, combined with the inherent uncertainty of genetic engineering, means that large-scale use of genetic engineering is dangerous. Threats posed by genetically engineered trees are simply too great to allow them to be released into the environment, much less to allow them to be mass cultivated in huge plantations (Langelle et al. 2006).

References

Black, DL. Splicing in the inner ear: a familiar tune, but what are the instruments? Neuron. 1998. 20(2):165-8. Alternative splicing; 576 inner ear variant proteins.

Chan, AWS, Chong, KY, Martinovich, C, Simerly, C, and Schatten, G. Transgenic Monkeys Produced by Retroviral Gene Transfer into Mature Oocytes. Science. 2001. 291:309-312.

Commoner, B, “Unraveling the DNA Myth: The spurious foundation of genetic engineering,” Harper’s February 2002.

Commoner, B. Failure of the Watson-Crick theory as a chemical explanation of inheritance. Nature. 1968. 220:334-340.

Crick, FHC. The Central Dogma of Molecular Biology. 1970, Nature 227:561-563 (quote on p. 563).

Gurian-Sherman, D. “Contaminating the Wild? Gene Flow from Experimental Field Trials of Genetically Engineered Crops to Related Wild Plants,” Center for Food Safety, 2006, Washington, D.C. www.centerforfoodsafety.org

Langelle, O,  Petermann, A,  Perry, A, Carman, N, Tokar, B, “Ecological and Social Impacts of Fast Growing Timber Plantations and Genetically Engineered Trees,” paper at October, 2006 International Union of Forestry Research Organizations Forest Plantations Meeting: Sustainable Forest Management with Fast Growing Plantations, Charleston, SC.

Nature. 2001. 409(6822): 860-921. International Human Genome Sequencing Consortium. Initial sequencing and analysis of the human genome. Nature article on Human Genome Project (public funding).

Pearce, F, “Altered trees hide out with the local poplars,” New Scientist, September 18, 2004.

Pursel, VG, Pinkert, CA, Miller, KF, Bolt, DJ, Campbell, RG, Palmiter, RD, Brinster, RL, Hammer, RE. Genetic engineering of livestock. Science. 1989. 244(4910):1281-8. Pigs that carry a gene for bovine growth hormone.

Schmucker, D, Clemens, JC, Shu, H, Worby, CA, Xiao, J, Muda, M, Dixon, JE, Zipursky, SL. Drosophila Dscam is an axon guidance receptor exhibiting extraordinary molecular diversity. Cell. 2000 Jun 9;101(6):671-84. Alternative splicing; 38,016 variant fruit fly proteins.

Smith, JM, Seeds of Deception: Exposing Industry and Government Lies about the Safety of the Genetically Engineered Foods You’re Eating. 2003. Yes! Books, 289 pp., Fairfield, Ia. www.seedsofdeception.org

Smith, JM, Genetic Roulette: The Documented Health Risks of Genetically Engineered Foods. 2007. Yes! Books, 319 pp., Fairfield, Ia. www.GeneticRoulette.com

Snow AA, Andow DA, Gepts P, Hallerman EM, Power A, Tiedje JM, Wolfenbarger LL.  Genetically engineered organisms and the environment: Current status and recommendations. 2004. Ecological Applications 15 (2):377-404. Policy recommendations and position paper by Ecological Society of America.

Suzuki, DT and Knudtson, P. Genethics: The Clash between the New Genetics and Human Values. Revised and updated edition. Harvard University Press. Cambridge, Mass. 1990.

Venter JC, Adams MD, Myers EW, et al. The Sequence of the Human Genome. Science. 2001. 291:1304-1351. Science article on Human Genome Project (private funding).

Watson, JD, Hopkins, NH, Roberts, JW, Steitz, JA, and Weiner, AM.  Molecular Biology of the Gene. 4th ed.  Menlo Park, Calif. Benjamin.Cummings, 1987.

UN Food and Agriculture Organization, “A Preliminary Review of Biotechnology in Forestry including Genetic Modification,” July, 2005.

Neil Carman represents the Sierra Club’s Genetic Engineering Committee.

Posted 30 September 2007