|Speaker:||Maxine Singer, President, Carnegie Institution of Washington|
|Topic:||“Genetically Engineered Plants”|
President Elect Collins called the 2126th meeting to order at 8:18 pm on January 26, 2001. The minutes of the 2124th meeting were read and approved.
The speaker for the evening was Maxine Singer, President of the Carnegie Institution of Washington, on the topic “Genetically Engineered Plants”.
Scientists are trained to adjust to change. Revolutionary change does not go down as easily with the non-scientific community. This attitude was reflected by Mark Twain when he said, “I don't mind progress; it's change I can't stand.” One revolutionary development now underway is genetically modified organisms (GMOs). Genetically modified plants offer great promise for some, while for others they seem to threaten great peril.
The genetic modification of plants follows hundreds of millions of years of natural selection, and thousands of years of artificial selection as agriculture developed. The earliest human grown plants reflect some degree of artificial selection. For example, corn could not have arisen by natural selection; the seed kernels can only be dispersed by human intervention, whereas in the probable ancestor, teosinte, the ripe kernels easily fall from the ear. Until the last century, artificial selection depended on the genetic mechanisms of natural selection.
When it was first used, the word “gene” stood for the abstract concept of an inheritable trait. Alleles are the range or set of possible variants of the single trait or gene and thus represent the natural variance of a gene. Variation can also occur in the modulation of a gene's expression. Alleles and gene regulation provide the variation for Darwin's natural selection.
GMOs have directed changes in their genetic material produced by recombination and cloning. Either a specific gene can be modified, or the regulation of the expression of a gene can be changed, or new genes can be introduced. Typically, the modified genes are cloned in bacteria, then recombined to isolate and transfer them back to the plant through a suitable vector.
During their evolution many organisms have accomplished this type transfer of genetic material between non-interbreeding organisms, called horizontal gene transfer, used in producing GMOs. The problem, other than public perception, is not the DNA that carries the gene but the protein that is ultimately expressed. The danger is not from the process, but from the product. We must judge the benefits for each modification in each plant on an individual basis. Are the proteins allergenic, or toxic to humans or to other organisms that will digest or be exposed to the plant?
BT corn and cotton are GMOs carrying a gene for parasporal crystal protein from strains of Bacillus thuringiensis that are toxic to the caterpillar of an insect pest called the European corn borer. The planting was 30 M acres in 1999. For 40 years previously the protein had been used by spraying the killed bacteria containing it directly on the plants. The costs and benefits analysis for using GMOs like BT must balance the biological effects and impact on the environment with the economic benefits. Chemical spraying destroys all insects indiscriminately and has a long-term effect on the environment. The increased use of insecticides in the US and Mexico, and habitat destruction in Mexico can account for the decline in the monarch butterfly. There is also the possibility that pollen contamination can lead to the development of resistance in non-target insects that could then be horizontally transferred to the target species. There apparently has been at least one case of bacterial spreading on watercress leading to the development of insect resistance.
The regulatory process for these decisions must be open to the public. Food is for many people a cultural and not a scientific issue. Whether golden rice, genetically enriched in vitamin A, will be acceptable in China, India or other countries will probably be determined more by cultural than by health considerations. We should adopt from the new technologies the best methods and results that improve productivity and thus lessen the environmental impact of agriculture caused by clearing. Anti-GMO efforts may be in part a reaction to industrial exploitation of small agriculture for economic purposes. They may also be honestly concerned with environmental impact issues. The public is suspicious of claims about the harmlessness and the economic benefits of these genetically engineered organisms.
There is a moral imperative to feed and improve the health of the world's people while preserving our planet. The public needs to decide whether to support the development of GMOs that can bring, on balance, real advantages to agriculture, health and the environment. With our full attention, we can avoid situations that result in harm and reap a good harvest.
Ms. Singer kindly answered questions from the floor. President Elect Collins thanked Ms. Singer for the Society and welcomed her to membership. The President Elect made the announcements about the next meeting, parking, and refreshments, and adjourned the 2126th meeting at 9:36 p.m. [These minutes were corrected by the Recording Secretary after they were read at the request of the speaker.]
|John S. Garavelli|
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