Humans have been genetically
enhancing other organisms through the practice of
selective breeding for thousands of years till today.
A Look around you: the beaked beans,kidney red beans,the sweet corn and
seedless watermelons at the supermarket, the purebred
dogs at the park, and your neighbor's prize rosebush are
all examples of how humans have selectively enhanced
desirable traits in other living things.
The type of genetic enhancement that generates the most
concern goes a step beyond selective breeding, however.
Technology now allows us to transfer genes between
organisms. For example, the tomato plant's beetle
resistance relies on a gene from a bacterium ( Bacillus
thuringiensis ), which scientists inserted into the tomato
plant's genome. This gene, called cry1Ac , encodes a
protein that is poisonous to certain types of insects,
including the beetle.
How is this done? Gene transfer technology is simply a
sophisticated version of a cut-and-paste operation. Once
the desired gene is identified in the native organism's
genome, it can be cut/taken out, transferred to the target plant,
and pasted/placed into its genome.... Once the new gene has
been introduced, the plant can be bred to create a new
strain that passes the gene from generation to generation.
Sit back relax and thinker something real and unreal about GMF,
think of some probable risks of growing plants that contain genes
from other organisms? Let's examine some examples: the beetle-
resistant tomato, the vaccination banana, the saltwater rice plant etc.
We've already covered the potential advantages of these plants, but what
are the concerns?
Cross-breeding with wild populations. For all of these examples, a primary
concern is preventing genetically modified versions from mixing with the
naturally existing populations of plants from which they're derived. Plants
rely on the transfer of pollen, via insects or the air, to breed and produce
offspring, and it's difficult to control how they cross-breed in the wild.
In most cases, it's not yet clear how introduction of the non-native gene
would affect wild populations(population control,epidemy,high or low mortality,increase in death retion,or improveded health care system or improved treatment ratio). Critics of genetically modified plant
technology cite the need to learn more about the potential long-term
impacts of genetically modified plants on the environment before mass-
producing them.
Toxicity or allergic reactions. Many people suffer from allergies to various
food items, including nuts, wheat, eggs, or dairy products. There is concern
that the protein products of introduced genes may be toxic or allergenic to
certain individuals.
When farmers start growing genetically modified crops, they stop growing
the old varieties. These old varieties are important sources of diverse genes
that give plants other desirable characteristics. For example, a new pest or
disease could come along and destroy the genetically modified rice. If one
of the old rice varieties has a gene that makes it resistant, it could be
cross-bred to make the saltwater rice resistant as well. If we lose the old
varieties, we also lose their useful genes.
It has been estimated that 70% of all processed foods in the United States
contain at least one genetically modified ingredient—usually a product of
soy plants. There are initiatives afoot to require food manufacturers to
provide clear labeling on processed food products that contain genetically
modified ingredients. This would make it easier for people with allergies to
avoid foods that might pose a danger to them, and it would allow those
who oppose genetically modified foods to opt out of buying them.
Unlike countries such as Australia and Japan, the United States currently
has no laws requiring companies to label products containing genetically
modified ingredients. With or without the controversy surrounding them, genetically modified plants have
taken root in our world. As with any new technology, members of society
have the responsibility to become informed about genetically modified
Plants and their products in order to make decisions.
No comments:
Post a Comment