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Chapter 12
Genetic Engineering
12-1 Modifying the Living World

What do the terms selective breeding,
inbreeding, and hybridization mean?

How can mutations be useful to humans?
Breeding Strategies

Farmers and ranchers have been trying to
improve organisms for years

By selecting the most productive animals
for the next generation, people have
found that the domesticated organisms'
productivity can be increased

Can be done by selective breeding,
inbreeding, and hybridization
http://www.wisdompanelpro.com/breedinfo/
Selective Breeding

Selective breeding-selecting a few individuals
to serve as parents for the next generation

Farmers are able to increase the yield of crops &
the milk production of animals by only breeding
animals that produce the most

Almost all the present-day crops were developed
through selective breeding
http://dels-old.nas.edu/plant_genome/booklet_part_2.shtml
http://www.tutorvista.com/content/biology/biology-ii/heredity-and-evolution/comparative-study.php
Inbreeding

Once the breeder has developed a good stock of
organisms, he wants to maintain that similar
stock

Inbreeding-crossing individuals with similar
characteristics so that those characteristics will
appear in their offspring (usually closely related)

Many varieties of purebred dogs are maintained
by inbreeding
http://phys.org/news138025054.html

Inbreeding is useful for getting certain
characteristics, it does have risks

The chances that recessive genetic
disorders will show up are higher because
most of the individuals have similar DNA

Examples: joint problems and blindness in
golden retrievers and German shepherds
is a result of this
http://fhoguide.com/FHO-hip-problems.php
Hybridization

Hybridization- cross between members of
different (but related) species

This produces hybrids that are usually hardier
than either of the parents (hybrid vigor)

Example: modern hybrid corn produces as much
as ten times the crop per acre of older varieties
of corn.
Hybrid vigor
http://passel.unl.edu/pages/informationmodule.php?idinformationmodule=1075412493&topicorder=9&maxto=12&minto=1
Mutations: Producing New Kinds of
Organisms

Selective breeding only involves
characteristics that already exist

Mutations can sometimes produce new
organisms with new characteristics

If mutations are wanted, the breeders can
produce new populations with those
desired characteristics
This definitely scares the mice!!
/
http://www.patheos.com/blogs/unreasonablefaith/2009/08/mouse-gets-benefitical-mutation-but-doesnt-evolve-into-crododuck
But seriously…seedless oranges
http://coastgrown.com/shop/product.php?productid=98

A mutation could take a long time to ever
happen so breeders my increase the
chances of a mutation

Mutagens-substances or agents which
include radiation and chemicals that cause
mutations

Mutations are usually harmful but with
luck and perseverance, a few mutants can
be produced with desirable characteristics
Could get some like this…probs not
http://www.dan-dare.org/FreeFun/Games/CartoonsMoviesTV/Pokemon2.htm

Mutagenesis (using mutagens to increase
mutation rate) is very useful with bacteria

With their small size and so many of them,
they are able to change at a much greater
scale

They are able to create useful bacteria
strains…one that even can digest oil
Oil digesting bacteria
http://news.softpedia.com/news/Bacteria-Eating-Up-Oil-Spills-and-Producing-Biodegradable-Plastic-18787.shtml
12-2 Genetic Engineering:
Technology and Heredity

What is genetic engineering? How does it
affect DNA?

How do the various techniques of genetic
engineering work?

What are some applications of genetic
engineering?
Genetic engineering

Biologists have developed ways that affect
DNA directly

They can engineer a sec of genetic
changes directly into an organism’s DNA

This is called genetic engineering
The techniques of genetic
engineering
http://www.ces.ncsu.edu/resources/crops/ag546-1/
Restriction Enzymes

Restriction enzymes-proteins that cut
out specific DNA sequences in genes

These recognize a site of four to six
nucleotides and then cut it out of the
strand of DNA

These make it possible to cut and isolate
specific DNA parts
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/R/RestrictionEnzymes.html
DNA Recombination

DNA fragments then need to be placed into part
of the recipient cell’s genetic material

The DNA is then combined with bacterial cells
DNA which are known as plasmids

Restriction enzymes cut the plasmids at certain
points so that the new DNA fragments can
combine with the “sticky ends” of the bacterial
DNA
http://en.wikipedia.org/wiki/Recombinant_DNA

This fuses DNA of two different organisms

Combined DNA is known as recombinant
DNA since DNA from two sources have
been recombined
DNA Insertion

How does this then get back into living
cells?

The easiest way is to place it into bacterial
cells and then grow them with the desired
DNA

This is known as DNA cloning because
growing a large number of cells grown
from a single cell is known as a clone

DNA can also be inserted into plants and
animals

Done by insertion with a glass needle and
fusion with plama-like DNA
DNA sequencing

The DNA then needs to be read

Only one stand is read but DNA cloning is done
to see multiple copies

DNA is broken into pieces with chemical
treatments

When separated they are able to see the
positions of the bases on the original strands

Separated by electrophoresis
DNA sequencing with
electrophoresis
http://en.wikipedia.org/wiki/DNA_sequencing
Engineering New Organisms

Organisms that contain such foreign genes
are said to be transgenic
http://www.scq.ubc.ca/the-new-macdonald-pharm/
Transgenic bacteria

Can create human growth hormones and
insulin which can help fight diabetes
http://tle.westone.wa.gov.au/content/file/c0a7f9da-2dc9-b549-578a-0f1a8921d148/1/bio_science_3b.zip/content/001_dna/page_15.htm
Transgenic plants
Tobacco plant with
Firefly genes

http://www.sciencedaily.com/articles/t/transgenic_plants.htm
CMV virus resistance
http://web.entomology.cornell.edu/shelton/cornell-biocontrol-conf/talks/gonsalves.html
Transgenic animals
http://www.nature.com/nbt/journal/v26/n11/full/nbt1108-1205.html
Transgenic Carp
http://www.cafs.ac.cn/english/Research-Priorities.html
Transgenic Mice
http://www.hms.harvard.edu/agingresearch/pages/whoweare.htm