Principles of Plant Genetics and Breeding

276 CHAPTER 15
Public perceptions and fears
about biotechnology
Stakeholders generally acknowledge that no technology
is without potential for adverse impacts. Another truth is
that the perception of technologies varies between the
scientists who develop them and the public who use
them. It is tempting to contrast public perception,
which is largely subjective, with scientific knowledge,
which is largely objective. Further, public perception is
viewed by some as basically illogical, irrational, and
based on emotions rather than scientific facts. There is
the temptation to condescend and disregard public
opinion as uninformed. However, scientists also have
perceptions of the technologies they develop that are
not necessarily rooted in facts, because the knowledge
available may be scanty or inconclusive. There is the tendency,
therefore, to either overestimate or underestimate
the benefits and risks of technology.
Because of the imperfections that plague both camps,
there are some misconceptions about biotechnology in
the general community that hinder its development and
application. A few of these will be introduced for the
sole purpose of initiating discussion on the subject.
Techniques of biotechnology are alien, unnatural,
and too radical
It was made clear in Chapter 1 that the definition of
biotechnology can be broad or narrow. In the broad
sense, organisms have been used to make products for
thousands of years (e.g., yeast in bakery products and
bacteria in fermented products). In the narrow sense,
biotechnology allows genes to be transferred unrestricted
among living things, in effect disregarding natural
genetic barriers. Whereas such interspecies gene
exchange is not the norm in nature, there are examples
of various degrees of such horizontal gene transfers,
especially on evolutionary time scales. Cross-pollinated
species propagate through gene mixing, normally
within the species. A more dramatic natural mixing
occurred in wheat – common wheat (Triticum aestivum)
is an allopolyploid (hexaploid) consisting of
three genomes of three different species. Certain
microbes have the capacity to transfer some of their
genetic material into the hosts they infect, even though
the outcome may be undesirable for the hosts.
In biotechnology, the gene transfer system of choice
in plants is Agrobacterium-mediated transfer. This bacterium
naturally transfers a portion of its genome into
the plant it infects, a bacterium to plant gene transfer
that forms galls in the plants. In biotechnology, scientists
capitalize on this natural process to transfer genes of
choice, only the result is not disease because the bacterium
is disarmed prior to use.
The normal direction of genetic information transfer
is from DNA to RNA to protein (the so-called central
dogma of molecular biology). However, there are certain
viruses that have RNA as genetic material. In retroviral
infections, the single-stranded RNA is reverse
transcribed to single-stranded DNA and then doubled
to double-stranded DNA. This is incorporated into
the host genome. Scientists can go a step further, and
replace the disease-causing components of the retroviral
genome with the desired genes for incorporation.
Mutations or heritable genetic changes occur naturally
as spontaneous events. Such natural gene alterations
produce variability for evolutionary processes to occur.
Instead of haphazard and random events, scientists are
able to induce the genetic changes that are desired.
It is obvious from these selected examples that science
merely imitates nature after studying to understand it.
Rather than random events, scientists attempt to nudge
nature purposefully to the advantage of humans. One
may argue that just because nature does it, does not
mean humans should do the same. But then another
may argue why not?
Genetic engineering is an exact science
It is true that specific genes can be identified, isolated,
and characterized. However, the current gene transfer
systems leave much to be desired. Once the DNA is
delivered into the cell, scientists are not able to direct
or predict where it will be inserted in the genome.
Consequently, scientists cannot predict precisely the
outcome of a transformation event. Where the gene
inserts itself in the genome has a bearing on its expression.
Even though this appears to be an uncontrollable
event that could lead to unexpected phenotypes, scientists
screen the products of transformation to identify
the individual(s) in which the transgene apparently has
been properly inserted and is functioning as desired. It
should be pointed out, that, compared with traditional
breeding in which transfer of a desirable gene is usually
accompanied by the transfer of numerous others, genetic
engineering is relatively very precise.
Pesticide resistance in the agroecosystem as a result of
the use of biotech crops is unavoidable
There are major crops in production with engineered,
targeted resistance to pests and herbicides. Pesticide-