Transgenic Bt Crops (Genetically
There are different ways of moving genes in a plant to produce desirable
traits. One of the more traditional ways is through selective breeding.
A plant with a desired trait is chosen and bred to produce more plants
with the desirable trait. More recently with the advancement of technology
is another technique. This technique is applied in the laboratory where
genes that express the desired trait is physically moved or added to enhance
the trait in the plant. Plants produced with this technology are considered
to be transgenic. Many times it is also referred to as Genetically modified
Results of insect infestation on Bt (right) and non-Bt (left) cotton
bolls. Source: USDA
Other GM products
Genetically engineered products are not new. Insulin used today in medicine
is an example of genetic engineering; the insulin gene from the intestines
of pigs is inserted into bacteria. The bacterium grows and produces insulin;
this insulin is then purified and used for medical purposes. Thyroid hormones,
until recently was derived only from animals, now the hormone can be cultured
from bacteria. Other genetically engineered products include the chemical
Aspartame used in sugar free foods, and the drug hepatitis B vaccine.
Engineering vs breeding
So why use molecular biology over traditional breeding? With traditional
breeding, plants often exchange large, unregulated chunks of their genomes.
This can lead to both useful and unwanted traits in the offspring. Sometimes
these unwanted traits can be unsafe. One example would be potato varieties
made using conventional plant breeding that inadvertently produced excessive
levels of naturally occuring glycoalkoloids. These glycoalkoloids cause
cause gastrointestinal, circulatory, neurological and dermatological problems
associated with alkaloid poisoning.
Breeders sometimes have to cross many plants over multiple generations
to produce the desired trait. GM techniques allow new traits to be introduced
one at a time without complications from extra genes and extensive crossbreeding.
GM techniques also allow traits from different organisms to be applied,
such as pest resistance.
Types of GM plants
Most GM crops grown today have been developed to resist certain insect
pests. There are GM plants being developed today to produce specific vitamins,
resist plant viruses and even produce medical …insulin. Countries
that grow GM crops include; Argentina, Australia, Canada, China, Germany,
India, Indonesia, Mexico, Portugal, South Africa, Spain, United States,
Ukraine, and many more.