Transcript LE - 7 - Genetic Engineering

Genetic
Engineering
What Do These Items Have In
Common?
DNA
• DNA (deoxyribonucleic
acid) is the genetic code
responsible for giving
organisms certain
phenotypes.
– By changing the DNA, we
can change the organism!
What is Genetic Engineering?
• A deliberate, controlled manipulation of genes in an organism
with the intent of making that organism better in some way.
• The use of various experimental techniques to produce:
– novel combinations of genes
– molecules of DNA containing new genes
Time to eat your
VITAMIN corn!
Genetic Engineering by Combining
Genes
• SELECTIVE BREEDING
– Allowing only those organisms with desired characteristics to
produce the next generation
What types of organisms have been selectively bred by humans?
– horses
– dogs
– cats
– farm animals
– most crop plants
Animal Breeding
Genetic Engineering Continued:
• Using genetic engineering, you can cross traits that belong in
different species.
– First, get a sample of the gene you wish to transfer from one organism to
another
– Use enzymes to cut certain DNA sequences that code for the desired
characteristic.
• Restriction Enzyme
How Restriction Enzymes Work
Restriction
Enzymes
make the
“cut” after a
certain code.
Like: Cut
after TTAA
sequence
Continued…
• Insert the code into tiny circles of bacterial
DNA called plasmids
• Allow plasmids carrying the gene to infect a
culture of bacterial cells
• Grow each of these cells as a pure cell
culture
• Through a screening process, select an
adequate gene that will stick to others via
A,T,C,G
Continued…
• Take selected object you want modified, open pores of the cell
membrane, and insert gene into cell.
• By various methods (like particle guns) selected genes will
combine with the natural DNA, therefore altering the original
sequence. This phase of genetic engineering varies depending
on the organism.
Gene Encoded on Plasmid
Genetically Engineering Causes
Genetic Modification
• By using this process, humans can “genetically modify” several organisms.
– Foods
– Animals
– Bacteria
• Genetically modified (GM) foods are foodstuffs produced from genetically
modified organisms (GMO) that have had their genome altered through
genetic engineering. GM Foods have been available since the 1990s
• Most common examples of GM foods:
–
–
–
–
–
Soybean
Corn
Canola
Wheat
Tomatoes
But WHY Do This?
• As stated before, the overall goal is to create a product better than the
original. We look at agriculture as our main example
In The Past
• Early forms of genetic modification were
done by hand
• The earliest Farmers altered the genetic
makeup of corn
• Corn's ancestor, a grass called teosinte, had
small ears with sparse kernels
• As humans selected teosinte ears bearing
the most plump kernels, they gradually
edged evolution towards forming a new
species, corn
• The jackets formed by the leaves covering
an ear of corn (husks) are so tight that the
plant cannot naturally release its seed. This
would not benefit a plant in the wild
Today’s Use
By altering the original DNA of the plants, we can create new plants with
several advantages. (Can you guess what these are?)
• pest resistance
• herbicide tolerance
• disease resistance
• cold tolerance
•
nutritional abundance
•
pharmaceutical additions
•
shelf life
Negative Effects
• Environmental activists, religious organizations, public interest groups,
profession associations, and other science and government officials have
raised concerns about GM foods and its potential hazards.
Potential Problems with GM foods include:
-
Allergens
Gene transfer to non-target species
Reduced effectiveness of pesticides
Unintended harm to other organisms
Should We Continue?
• 75% of all crops grown in the U.S. contain some type of GM
gene at varying degrees
• These enhanced plants are not only good for the American
wallet, but they can help other third world countries in fighting
starvation
• Do you agree with the use of GM foods?
Genetic Modification on Animals
• The latest trend in genetic engineering is now experimentation on animals
Pharming
• Genetic modification on farm animals has potential to lower prices and
enhance enrichment, however, the ethics behind this are very strong, so
research is kept at bay.
• Two common types of pharming include injecting cows with hormones so
that the milk they produce will have proteins of potential medical benefit as
well as pharmaceutical products
Question: Does cow milk contain Vitamin D?
Answer: NO! The hormone is injected after pumping, Adding Vitamin D
to milk is like adding Iodine to salt….GM eliminates a step in the food
processing process.
Pharming
• A recent genetic modification concerns breeding featherless
chickens. Because there are more chickens than people in the
world, plucking is very time consuming and costly.
Genetic Modification of Bacteria
• Scientists can modify the gene code of bacteria.
– Bacteria can now produce insulin or other hormones
people need.