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SELECTING DESIRABLE TRAITS
ARTIFICIAL SELECTION

The process of selecting an breeding individuals
with desirable traits to produce offspring that
have these desired traits. Humans choose, not
nature!
IN NATURAL SELECTION


The environment “selects” traits. In artificial
selection, humans select traits.
For example, scientists working at Alta Genetics
Inc. of Calgary were the first to use genetically
engineered cattle that would produce more beef.
REMEMBER THE GENETICALLY MODIFIED
CHICKENS IN “VEGUCATED?”
MOST OF WHAT YOU EAT IN A DAY IS PROBABLY
A PRODUCT OF ARTIFICIAL SELECTION

Grains

Fruits

Vegetables

Meats

Nuts
CONSIDER HORSE BREEDING

By combining genes of champion parents,
breeders hope to create offspring that have the
traits of both parents.
IN A BREEDER’S POPULATION, EVERY
INDIVIDUAL IS SELECTED IN THE SAME WAY…
 Only
those with the trait the
breeder wants will be allowed to
breed.

In contrast, natural selection, “selects” traits that
are useful for the for the survival of the
individuals with those traits and allows them to
breed.
NATURE VS NURTURE?

The owner of a prize stud can earn about $30
million per year.
NATURE VS NURTURE


"The offspring of expensive stallions might tend
to win more money, but not necessarily because
they have inherited the best genes," said Wilson.
"It is likely those breeders best able to pay high
stud fees are also those who are able to spend
more on care of the horse, how it is trained, and
who rides it - all of which will contribute more to
how much it will win."
HUMANS PRACTICED ARTIFICIAL SELECTION
FROM THE TIME WE FIRST BEGAN TO FARM



About 10,000 years ago
Most of our plants no longer resemble the wild
species from which they were bred.
E.g. Corn/Maize
TEOSINTE
BIOTECHNOLOGY
 Aboriginal
peoples practiced an early
form of biotechnology.
THEY GATHERED SEEDS…
From
the biggest and healthiest
corn plants.
This
benefited them because
they were able to develop more
productive strains of corn.
ALTHOUGH ARTIFICIAL SELECTION HAS PRODUCED
MOST OF WORLD’S CROPS AND LIVESTOCK…
 It
takes a very long time (many
generations) to get an organism with the
desired combination of traits.
FOR EXAMPLE…
 Livestock
breeders have to breed cows
over many generations to get a while herd
that produces large quantities of milk.
 Scientists
and breeders have developed
technologies that can speed up this
process.
CLONES…
CREATING PLANT CLONES

The simplest way to create a clone is by taking a
cutting from a plant and growing an identical
plant from the cutting.
THE DRAWBACK IS….


That this ideal plant has only so many leaves
that can be cut off to use as cuttings.
So scientists have developed a quicker way: cells
are removed from an individual plant that has
the particular traits that are wanted.


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These cells are placed on a Petri dish or bottle
containing nutrients and hormones the cells
need.
Once these cells have developed into seedlings,
they can be transplanted into the coil.
Many more clones can be produced from a single
plant this way.
ARTIFICIAL REPRODUCTIVE TECHNOLOGY

Is an artificial way of joining a male and female
gamete.
MOST LIVESTOCK IN CANADA ARE
PRODUCED IN THIS WAY.


In artificial insemination sperm are harvested
from a bull desired characteristic and are
inserted into many female cows.
The advantage is the that the sperm can be in
many places at once and more cows can be
inseminated.
IN VITRO FERTILIZATION

In this technology, sperm from a prize bull and
eggs from a prize cow are harvested from the
animals, and in a lab, placed in a Petri dish.
THIS PRODUCES MANY MORE EMBRYOS
THAT COULD BE PRODUCED NATURALLY.

Each embryo is implanted in a different cow.
These cows will give birth to many calves, all of
which will be brothers and sisters.
SCIENTISTS CAN ALSO DETERMINE THE
SEX OF THE EMBRYOS…


Before they are implanted in the cows.
By choosing only females, dairy farmers can be
guaranteed that all of their calves will be female,
rather than having to use their resources to raise
unneeded males.
FIRST HUMAN “TEST TUBE” BABY

On July 25, 1978, Louise Joy Brown, the world's
first successful "test-tube" baby was born in
Great Britain.
USING A LONG, SLENDER, SELF-LIT PROBE
CALLED A "LAPAROSCOPE," …

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Dr. Steptoe took an egg from one of Lesley
Brown's ovaries and handed it to Dr. Edwards.
Dr. Edwards then mixed Lesley's egg with John's
sperm.
After the egg was fertilized, Dr. Edwards placed
it into a special solution that had been created to
nurture the egg as it began to divide.
PREVIOUSLY… IT TOOK MORE THAN ONE
TRY TO GET THE SCIENCE RIGHT…


Drs. Steptoe and Edwards had waited until the
fertilized egg had divided into 64 cells (about four
or five days later). This time, however, they
decided to place the fertilized egg back into
Lesley's uterus after just two and a half days.
Close monitoring of Lesley showed that the
fertilized egg had successfully embedded into her
uterus wall.
WHY WAS THIS NEW TECHNOLOGY
CONSIDERED BENEFICIAL (A GOOD THING)


For human beings?
What concerns/potential problems can you
identify?
GENETIC ENGINEERING
Refers
to any technology that
directly alters the DNA of an
organism.
A
rapidly developing science,
and every new advance
increases our ability to control
the characteristics of organisms.
GLOFISH…IS A PATENTED AND TRADEMARKED
BRAND OF GENETICALLY MODIFIED FISH.
MONSANTO

Video Link
MANY OF THE GENETIC ENGINEERING
TECHNIQUES…
Involve inserting a gene from one species into
another species.
 Bacteria are genetically engineered to produce
life-saving medicines such as insulin.

20 YEARS AGO…

Insulin had to be extracted from the pancreas of
cattle and was expensive to produce.
Today,
the human insulinproducing gene is inserted
into the bacteria’s DNA.
BECAUSE BACTERIA REPRODUCE SO
RAPIDLY…

Bacteria colonies can produce insulin quickly and
cheaply.
BACILLUS THURINGIENSIS PRODUCES A
TOXIN CALLED BT

BT is poisonous to many insects.
SCIENTISTS ISOLATED THE GENE THAT CONTAINS THE
INSTRUCTIONS FOR MAKING BT TOXIN…


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And have inserted it into the DNA of plants.
These genetically engineered plants now produce
Bt toxin.
Since the 1990s, cotton, corn, and potatoes have
been engineered to produce Bt toxin.
Because insects that eat the engineered plants
die, farmers never have to use pesticides to
engineered plants.
SOME VARIETIES OF CANOLA ARE NATURALLY
RESISTANT TO FLEA BEETLE, WHILE OTHERS ARE
NOT.

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The most valuable varieties are not naturally
resistant, so most growers use pesticides.
Why might this be a problem?
Scientists have just figured out how to transfer
the resistance gene to non-beetle resistant
varieties.
BIOTECHNOLOGY AND SOCIETY

As with any technology, there are risks and
benefits.
ARTIFICIAL REPRODUCTIVE
TECHNOLOGIES …


Can reduce the variation in breeding lines of
livestock; the sperm of just a few animals is used
to impregnate many females.
With in vitro fertilization, the embryos created
from the eggs and sperm of just 2 individuals is
implanted in many other cows.
CLONING…

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Remember “Dolly” the sheep?
Produced in 1997, Dolly was an exact duplicate of
her mother. Dolly’s cells appear to be the same
age as her mother’s, even though Dolly is 6 years
younger.
Herds of such genetically identical individuals
may be far more susceptible to disease than more
genetically variable herds.
CLONING AND GENETIC ENGINEERING…
Are in their infancy and have been full of
problems.
 Some researchers hypothesize that something
about the process of removing the nucleus from
the donor egg may be responsible.

CATTLE CLONERS…

Have reported many examples of unsuccessful
pregnancies, birth defects, and deaths.