Field Testing Genetically Modified Organisms Framework for Decisions (1989) / Chapter Skim
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2 Introduction
2 Introduction
Pages 7-15
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From page 7... ...
Hence, this NRC committee was formed to attempt to determine a reasoned consensus about what scientific questions must be asked and how such questions can aid In the development of a decision-making process based soundly on the facts of science. The history of efforts to reach a common ground about the relative safety or hazard of genetic modification of organisms can be traced directly to the early 1970s, when advances In biological knowledge had given scientists the tools to recombine DNA ~ the laboratory into new sequences (see Appendix)
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From page 8... ...
The evolution of new forms of crop plants and microorganisms results from selecting organisms with desirable traits from populations that possess heritable variation. When genetic variants are selected to produce the next generation, the population is changed with respect to the frequency of individuals having the selected characteristic.
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From page 9... ...
Another example relates to the natural transfer of DNA from the bacterial species Agrobacterium to plant cells (Nester et al., 1984~. Plasmid genes from this bacterium probably were transferred into a species of tobacco early in the evolution of the genus Nicotiana, and they became integrated into the plant chromosome.
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From page 10... ...
Because interspecific hybrids, and even many intraspecific hybrids, have a parent that may be poorly adapted to survive and grow in an agriculturally useful way, considerable effort Is required to examine large numbers of plants to find the desired combinations of traits. Two major limitations exist with classical plant breeding.
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From page 11... ...
Current research is directed toward introducing DNA into specific plant tissues that have the greatest probability of regenerating genetically modified plants. COMPARISON OF CLASSICAL AND MOLECULAR TECHNIQUES IN PLANTS The major difference between classical and molecular techniques is the greater diversity of genes that can be introduced by molecular techniques and the greater precision of these introductions.
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From page 12... ...
These regions determine specific conditions for gene expression, for example, in the light, In specific tissues, or at certa~n stages of development (Goldberg et al., 1989~. On the basis of this knowledge and recombinant DNA technology, one can attach the desired region of a gene to a bacterial gene and introduce the combination into a plant cell, where it will be expressed In a specific tissue.
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From page 13... ...
The genus barrier and, indeed, the kingdom barrier are no longer complete obstacles. Recombinant DNA methodology makes it possible to introduce pieces of DNA, consisting of either single or multiple genes, that can be defined in function and even in nucleotide sequence.
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From page 14... ...
With classical methods of mutagenesis, chemical mutagens such as alkylating agents modify DNA In essentially random ways; it is not possible to direct a mutation to specific genes, much less to sped cific sites within a gene. ~deed, one common alkylat~g agent alters a number of different genes simultaneously.
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From page 15... ...
Scientists have vast experience with the products of classical modification, and the knowledge gained thereby is directly applicable to understanding, evaluation, and decision-mak~g about the relative safety or risk of field tests on products of molecular modification techniques.
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