Transcript Interbreeding

Selective Breeding & Genetic
Engineering
What we want to learn!
• Summarize how transgenic organisms are
engineered to benefit society.
• Explain how transgenic organisms are used in
agriculture, industry, and medicine.
Selective Breeding
• For thousands of years, humans have selected
plants and animals with certain qualities or
desired traits.
• They’re bred with other plants and animals with
desired traits.
• The same principle is applied today to the food
we eat and the animals that we raise!
▫ Selective Breeding-selected organisms bred with
one another to produce offspring with desired
traits.
Selective Breeding Examples
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Seeds from the largest heads of grain
Seeds from the juiciest berries
Raise the calves of the best milk producers
Save the eggs of the best egg laying hen for
hatching
..........all of these examples show you how selective
breeding is done!
………the goal is to try and ensure your outcome is
the animal or plant of choice!
Selective Breeding
• This process takes time and multiple generations
before the desired result is reached.
Desired Result: a population breeds consistently
so that each member shows the desired trait.
Interbreeding
• Interbreeding-mating between closely related
organisms
▫ Results: an organism that has the same genes for
each trait! This organism is almost guaranteed to
now have the desired traits!
▫ ie. pure bred dogs
▫ ie. Pure bred horses
• Hybrids- the result of the interbreeding
▫ Usually higher functioning, larger & stronger than
their parents.
Genetic Engineering
• Genetic Engineering is a faster, more reliable
method of increasing a desired trait
• DNA is cut – or cleaved from one organism into
small fragments and inserted into a host of the
same or different species
......Genetic engineering is also referred to as
recombinant DNA technology
▫ Recombinant DNA- connecting, or recombining,
fragments of DNA from different sources.
Original plasmid has a enzyme
recognition site.
The plasmid is then cut by the enzyme
(ie.Eco R1) ; when DNA is cut, you end
up with double stranded fragments
with single stranded ends.
Foreign DNA is then inserted into the
plasmid ; giving you a recombinant
plasmid (recombinant DNA)
Transgenic organisms contain
recombinant DNA
• Recombinant DNA can be inserted into a
organism’s chromosomes
▫ Chromosomes: carries your genetic information
• That organism will use this foreign DNA as its
own.
Restriction Enzymes
• Isolate the foreign DNA fragment that will be
inserted.
▫ Restriction enzymes are proteins that have the ability
to cut both strands of the DNA at specific areas.
• Attach DNA fragment to the carrier
▫ Vectors: carries the DNA into the (host) DNA
▫ ie. The glowing tobacco leaf ; light producing DNA had
to be placed into a bacterial vector before it could be
inserted inside the plant
• Transfer into host organism.
▫ Plasmid-small ring of DNA found in a bacterial cell
Vectors
• …so far we’ve learned that restriction enzymes
cut the DNA that is taken from organism A.
• If the same restriction enzyme is used to cleave
the plasmid the DNA of organism A should join
together with the plasmid ring.
First in this diagram you have
the plasmid vector. The
Gene cloning
• After desired genes and desired are “united”..the
recombinant DNA is then cloned.
• The plasmid is capable of replicating separately
from the bacterial host.
• DNA is reproduced quickly.
DNA Technology