Transcript Acc_Bio_Biotechnology_12

Genetic Technology
Section 11.1
What is Biotechnology?
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Biotechnology is using living organisms to
produce something useful for humans
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Selective breeding – breeding organisms to
produce desirable traits
Inbreeding – crossing of organisms that have
similar genotypes so the desirable traits will
eventually be homozygous (crops, horses,
dogs . . . not people!)
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Can also increase the chance of harmful recessive
traits showing up
Consider Dalmatians . . .
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A white coat with crisp spots is
the desired look breeders want
However, the presence of white
in the hair coat increases the
likelihood of deafness
Breeders were selecting for the
perfect coat color, but at the
same time they were also
selecting the gene for
congenital deafness!
8% of all Dalmatians in the US
are bilaterally deaf and 22% are
unilaterally deaf
Hybridization
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Outbreeding – crossing distantly related
organisms
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Combines desirable traits from different parents
Hybrid vigor – larger, healthier offspring may be
produced, but often sterile if different species.
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Mule from male donkey and female horse is more docile
than donkey but hardier than a horse
Genetic Engineering
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Genetic engineering – manipulating genes
for practical purposes.
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Can yield changes in a very short period of
time
Cohen and Boyer (1973)
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Stanley Cohen and Herbert Boyer
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They isolated the gene that codes for rRNA
from the DNA of an African clawed frog.
They inserted the gene into E. coli bacteria.
During transcription, the bacteria produced
frog rRNA!
Changing Genomes
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Recombinant DNA – formed when DNA is
combined from different organisms
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Human genes that produce human proteins can be
added to bacteria or yeast to mass produce the
proteins
Mechanism of Recombination, 3D animation with
with basic narration
Genetic Engineering to Procuce Insulin
Changing Genomes
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Vector – carrier of the DNA
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Plasmid – small circular
pieces of DNA found in
bacteria
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Genes are spliced into the genome
of the vector by utilizing restriction
enzymes and sticky ends
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Restriction Enzymes –
recognize specific DNA
sequences and cut the DNA
between specific nucleotides
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Sticky Ends – pieces of
DNA with short single
stands on each end that are
complimentary to each other
Making
INSULIN
Human
DNA
Restriction
enzymes
cut the
DNA
DNA
Fragments
with “Sticky
Ends”
Restriction
enzyme cuts
the plasmid
Small,
Circular,
Bacterial
DNA =
Plasmid
Insulin gene
inserted into
plasmid
rDNA used
as vector
Eaten Cheddar Cheese Lately?
One of the most successful applications of recombinant DNA technology
for foods is the production of chymosin, an enzyme used in cheese
making. Chymosin, when added to milk, causes the curd to form.
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Chymosin, which was available only from the stomach of calves, was
in limited supply due to a reduction in the veal industry and
expansion of the cheese industry.
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Then the gene for chymosin production was incorporated into the
DNA of both bacteria and yeasts. Pure chymosin can now be made.
The enzyme is identical to that produced in the calf and the process
itself adds no contaminants. The FDA evaluated the safety of the
process and the product itself in 1990 and ruled that the enzyme
preparation was safe for human consumption.
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Most Americans who have had a slice of Cheddar cheese since 1990
have eaten a product improved by biotechnology.