Transcript Genetic Engineering

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How are these
organisms different?
Are they the same
species?
Who is involved with
making these
variations?
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How are these
apples different?
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Are they the same
species?
•
Who is involved with
making these
variations?
The principles of genetics are being used to change the world!
Selective Breeding
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Selective breeding, or artificial selection, is
when people take control and cross
organisms with selected traits.
• Humans use selective breeding to pass
desired traits on to the next generation
of organisms.
– For example, domestic dogs are bred for
desirable physical characteristics and health
traits.
– For example, most crop plants are crossed for
desirable tolerances to temperatures and
diseases.
Hybridization
“Get a mutt, its healthier!”
 Hybridization = crossing dissimilar
individuals to bring together the best of
both organisms
 Hybrids = hardier individuals produced
by hybridization.
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Inbreeding
“Pure bred dogs are just as healthy”
 Inbreeding = the continued breeding of
individuals with similar characteristics
 One major problem: Inbreeding is more
likely to cross two recessive alleles
producing genetic defects.
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Concept Map
Section 13-1
Selective
Breeding
consists
of
Inbreeding
Hybridization
which
crosses
which
crosses
Similar
organisms
Organism
breed A
Organism
breed B
Organism
breed A
which
Retains
desired
characteristics
Go to
Section:
for
example
for
example
Dissimilar
organisms
which
Combines
desired
characteristics
What about Variation?
Some scientists try to preserve the
diversity in our world
 Other scientists try to increase the
diversity in our world = more variation!
 Breeders can increase the genetic
variation in a population by inducing
mutations, which are the ultimate
source of genetic variability!
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Mutations
Remember: Mutations are inheritable
changes in DNA.
 You can wait for mutations to occur
spontaneously, or you can increase the
rate of mutations by using radiation or
chemicals
 Mutations can be harmful or desirable
to an organism!
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Some Mutant Examples
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New Bacteria: Scientists have been able to
develop hundreds of useful bacterial
strains with mutations.
 For example, bacteria that digests oil and cleans
water after oil spills
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New Plants: Scientists have been able to
develop drugs that prevent chromosomal
separate during meiosis in plants.
 For example, polyploid plants have many sets of
chromosomes and are larger and stronger
This is all Genetic Engineering!
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Genetic engineering changes the
arrangement of DNA that makes up a gene.
Genes can also be inserted into cells to change
how the cell performs.
• For example, large volumes of medicines, such as
insulin, can be produced or plants resistant to
diseases can be developed.
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Biotechnology is a branch of science studying
genetic engineering and changing the way we
interact with the living world.
Other Uses of Genetic Engineering
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In the past, people breed for organisms with desired traits by
selective breeding, but now people can insert genes (DNA)
into cells to produce organisms with those same desired
traits by genetic engineering (Cell Transformation)
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Gene therapy is a form of genetic engineering that inserts a normal allele
into a virus that attacks a target cell and inserts the normal allele into the
body.
Cloning is the process of making a new identical copy of an
organism from a single adult cell. Cloning can occur naturally
as twins, or to genetically engineer plants and animals,
endangered or extinct species, a deceased pet or human, or
stem cells.
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Stem cells are the cells that all of your cells “stem” from. Stem cells can be
used to determine the function of specific genes, manipulate genes, or make
new cells or tissue to treat injuries or diseases.
Let’s Review
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Selective Breeding:
 Hybridization = dissimilar individuals
 Inbreeding = similar individuals
Let’s Review
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Increasing variation:
 Mutations = alter/change DNA
 Polyploidy = interfere with meiosis
Let’s Review
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Genetic Engineering:
 Cell Transformation = insert foreign DNA into
a cell
 Cloning = use a single adult cell to produce
a genetically identical duplicate individual
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What do you think are some of the pros
and cons of genetic engineering?
Pros and Cons of Genetic
Engineering
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Pros
Better Taste, Nutrition and Growth Rate
Crops like potato, tomato, soybean and rice
are currently being genetically engineered
to obtain new strains with better nutritional
qualities and increased yield. The
genetically engineered crops can be used
to impart a better taste to food.
Pest-resistant Crops and Longer Shelf life
Engineered seeds are resistant to pests
and can survive in relatively harsh climatic
conditions. It can thus result in fruits and
vegetables that have a greater shelf life.
Genetic Modification to Produce New
Foods
Genetic engineering in food can be used to
produce totally new substances such as
proteins and other food nutrients. The
genetic modification of foods can be used
to increase their medicinal value, thus
making homegrown edible vaccines
available.
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Cons
May Hamper Nutritional Value
Genetic engineering in food involves the
contamination of genes in crops.
Genetically engineered crops may
supersede natural weeds. They may prove
to be harmful for natural plants.
May Introduce Harmful Pathogens
Horizontal gene transfer can give rise to
new pathogens. While increasing the
immunity to diseases in plants, the
resistance genes may get transferred to the
harmful pathogens.
May Lead to Genetic Defects
Gene therapy in human beings can have
certain side effects. While treating one
defect, the therapy may lead to another.
Detrimental to Genetic Diversity
Genetic engineering can hamper the
diversity in human beings. Cloning can be
detrimental to individuality.