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why pretend plant breeding and genetic engineering are similar?
The article below shows the view of plant breeding in comparison to
genetic engineering that is being promoted by the corporations selling
GM crops and one taught in US and Canadian Universities. However, most
students of genetics must realize that the view is fundamentally false.
The reason that it is false is that the means by which the crops were
created. Domestication and plant breeding depend upon meiotic
(homologous) recombination while genetic engineering of plants employs
only illegitimate recombination. The illegitimate recombinants arise
from gene insertions following chromosome breakage. The illegitimate GM
crops are fundamentally different from bred or domesticated crops and
the illegitimate insertions lead to problems of instability. It is hoped
that intellectual honesty will ultimately prevail over the need to
promote GM crops for rapid dispersal.
Gepts, P.
Crop Science 42:1780-1790 (2002)
A Comparison between Crop Domestication, Classical Plant Breeding, and
Genetic Engineering
Several claims have been made about genetic engineering (GE) in
comparison with crop domestication and classical plant breeding,
including the similarity of genetic changes between those taking place
during domestication and by GE, the increased speed and accuracy of GE
over classical plant breeding, and the higher level of knowledge about
the actual genes being transferred by GE compared with classical
breeding. In reviewing evidence pertaining to these claims, I suggest
that (i) it is unlikely that changes introduced by GE will make crops
weedier, although exceptions have been noted, (ii) changes brought about
by GE currently often involve gain-of-function mutations, whereas
changes selected during domestication generally involve loss-of-function
mutations, (iii) adoption of GE cultivars has been much faster than any
previous introduction and spread of agriculture that occurred earlier
but has occurred at about the same rate as the spread of cultivars
obtained by plant breeding, (iv) introduction of agriculture reduced the
health of agriculturists compared with that of hunter–gatherers,
suggesting that introduction of innovations do not automatically improve
well being, (v) although GE is not a substitute for plant breeding, it
can significantly contribute to plant breeding by generating additional
genetic diversity, (vi) uncertainties associated with the site of
insertion of transgenes in the genome and the expression of transgenes
following insertion, makes GE less rapid and precise than originally
claimed, and (vii) a potential advantage of GE over classical breeding
is the knowledge of the actual gene(s) being inserted, although few
cases of unwanted gene introductions through classical plant breeding
have been documented. Further advances in GE will increase the precision
of the technique, its relevance to consumers, and its environmental
friendliness. What is most needed are even-handed, case-by-case
assessments of the benefits and potential pitfalls of GE in comparison
with other crop improvement techniques. Classical plant breeding may, in
the end, also be regulated in the same way as GE.
.