Biotechnology

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23 Οκτ 2013 (πριν από 3 χρόνια και 9 μήνες)

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Probing Question


Throughout history humans were not
always able to extract DNA and physically
manipulate it. How did people in past
overcome this obstacle?

Biotechnology


Application of biological science to solving
practical problems


Two Methods:


I.
Breeding Strategies




A.
Selective Breeding/Artificial Selection



-

indirect manipulation of DNA



-

select parents with desirable traits




-

goal
-
directed: create “better” individual



-

oldest way to improve a species



-

breed


The Evolution of Corn


10,000 years ago ancient
farmers in Mexico choose
which kernels (seeds) to
plant


Noted not all plants were
the same
-

size, taste of
kernels, ease to grind


Over time Maize cobs
became larger, more rows
of kernels

Maize cobs uncovered by archaeologists show the evolution
of modern maize over thousands of years of selective
breeding. Even the oldest archaeological samples bear an
unmistakable resemblance to modern maize.


Photo © Robert S. Peabody Museum of Archaeology, Phillips
Academy, Andover, Massachusetts. All Rights Reserved.

Genetic Archaeology


Corn’s wild ancestor is a grass called
teosinte


Types of Selective Breeding

1. Inbreeding


-

to maintain traits in a population


-

mate parents with similar genomes


-

keeps desirable traits, but increases risks for
undesirable mutations

2. Outbreeding (Hybridization)


-

crossing of distantly related organisms


-

offspring often sterile but hardier
(hybrid vigor)


-

in nature hybrids can often survive where
parents cannot; they find a different niche




Mule

Male lion and tigress = liger

Male tiger and lioness = tiglon

Sea Life Park Hawaii
RECOMMEND


A
wholphin

(dolphin
-
false killer
whale) named
Kekaimalu
.

A Fullblood Beefalo is an
animal containing 3/8 American
Bison and 5/8 domestic cattle.
This combination produces a
fertile animal which develops
rapidly and provides excellent
table meat.

American Beefalo cattle
combine the hardiness of the
Bison with the temperament of
bovine breeds. The bovine
bloodlines can be of any breed
enabling a Beefalo breeder to
select the bovine genetics best
fitted to his individual program.

Broccoflower

Killed by a hunter last month in the
Canadian Arctic, this male bear was
confirmed via DNA analysis last
week to be half grizzly, half polar
bear. John Roach

for
National Geographic News


May 16, 2006



Photograph from Canadian Wildlife
Service/AP




“Some biologists
estimate that as many
as 10 percent of
animal species andup
to 25 percent of plant
species may
occasionally breed
with another
species.” NYT
9.14.10


What is the
biological species
concept?

If hybrid is fertile
and survives…


B. Other “Breeding” Options



1.
Use of Mutagens (Mutagenesis)



-

radiations or chemicals to cause

mutations



-

used in bacteria



2.
Induced Polyploidy



-

chemical which causes cells to have extra set of
chromosomes



-

fruits, flowers, and plants larger



-

*some cases such as plants and lower animals


natural occurrence



-

lethal for human zygote





II. Genetic Engineering


-

direct manipulation of DNA


-

cutting and pasting of genes


-

design organisms or create transgenic
organisms


-

transgenic organism
-

organism with foreign
DNA or rDNA


-

recombinant DNA

(rDNA)
-

DNA molecule
made of DNA fragments from two different
species
(ex. Bacteria and human)


-

vector
-

agent/vehicle used to transport rDNA or
gene of interest into organisms


Using recombinant DNA
technology we can make
transgenic…


Bacteria


Plants


Animals



How do you feel about genetically altering
a species from its normal state?

What useful applications of this
biotechnology exist?


Which transgenic species will prevail
as the leader in biosteel production?


SPIDER

GOAT?

STEELY

SILKWORM?

Steps involved in creating spider
-
goats:

1.
Identify the genes associated with
“silk”production.

2.
Genetically engineer (clone) the genes

3.
Implant genes into embryo of the goat

Figure 6.28Microinjection of DNA

Cloned plasmid
DNA

is being microinjected into the male
pronucleus of a fertilized mouse egg.

From: Section 6.3, Manipulating the Genes of Eukaryotes

A DNA construct can be injected into 0.5
-
day
-
old fertilized
embryos to produce transgenic mice containing the DNA in
every cell. The DNA construct typically consists of a gene
of interest that is expressed in a certain range of tissues. The
resulting mice are mated and the DNA construct is then
transmitted to offspring.

Rat Growth Hormone
-
Metallothionein
Gene Construct. The gene for rat growth
hormone (shown in yellow) was inserted
into a plasmid next to the metallothionein
promoter, which is activated by the
addition of heavy metals, such as cadmium
ion.

http://www.ncbi.nlm.nih.gov/books/NBK22390/

Spider
-
goats continued…

4. Lactation

5. Distillation

6. Purification

7. Spinning

8. Stretch the fiber

In groups…


Discuss questions and record your answers
your notebook.


Add the following question, “Is silk
production in goats an acceptable use of
biotechnology?”

As you watch each of the
following record your thoughts
and/or questions.

Human anti
-
clotting Protein produced in the
goat’s milk

Engineered mice with green fluorescent protein

Engineering rainbow trout to increase their muscle
mass

Are these instances acceptable
uses of biotechnology?

Biomimicry
-

the study of genetically
manipulating one species to have a specific
trait of another species.


What are the various uses for goat silk that
were described in the video? Explain how
the silk would be effective for each use?


Why is it not practical to use spider farms to
harvest the silk fibers?


Is silk production in goats an acceptable use
of biotechnology?


Has your opinion of genetically altering a
species changed?

What information needs to be
known up front?


Transgenic Animals

Recombinant DNA can be introduced by:

1.
DNA microinjection

2.
Retrovirus mediated gene transfer

Steps to Make a Transgenic
Bacterium

1.
DNA Extraction
-

get genome from
organism containing gene of interest

2.
Splice gene of interest from genome using
a restriction enzyme(RE)


-

RE, chemical that cuts DNA at a
recognition site(short sequence of bases)

3.
Splice bacterial plasmid using same RE


-

plasmid: circular piece of DNA in
bacteria video clip

Plasmid
may not
be
exactly
circular

http://www.ncbi.nlm.nih.gov/books
/NBK22390/

Making recombinant
plasmid(DNA)

Red= bacteria DNA

Blue= human insulin
gene

-

Details making recombinant plasmid
(DNA)

a. Due to sticky ends,
gene can be spliced
in

b. DNA ligase help
nuclotides bond

c.
Combined DNA
called rDNA or
chimera

d.
Put rDNA back into
bacteria and grow in
culture

Insertion of Gene of Interest into
Plasmid






Using rDNA plasmid to create a
transgenic plant

A virus is
another
biological
vector also
used to
deliver genes

IF you had to genetically engineer a bacteria to
to transport a gene into a tobacco plant, which
would you choose?

Mechanical Vectors:

1. Gene Gun

2. Pipette

http://www.agriculture.purdue.edu/agbiotech/images/Genegun1.html

Transgenic Organisms


GOAT GOODS. A transgenic goat
named Artemis produces in her milk a
human
-
breast

milk compound called
lysozyme. Lysozyme destroys bacteria
by drilling through their cell walls.

E. Scharfen

3. Gel
Electrophoresis


a. Method of separating
DNA fragments according
to their size


b. DNA slightly (
-
) charge,
will run towards (+) charge


c. Shorter DNA fragments
will move farthest


d. Check to see if DNA
was cut by RE