Selective breeding is a type of engineeringSelective breeding is a type of engineering that we have done for a long time • See how chickens have been changed by using the selection

Selective breeding is a type of engineering

that we have done for a long time

• See how chickens have been changed by using the

selection process, and see how you never know

what you might get that you didn’t plan for.

• http://www.youtube.com/watch?v=OpvPu3hkDb8

• Now here is a good short intro to the most modern

way to get organisms with traits you desire, as

well as some of the ethical aspects.

• Gene editing 5 Min.

http://www.youtube.com/watch?v=OpvPu3hkDb8

https://www.youtube.com/watch?v=I5_2c52OPFw

• Here’s one thing genetic engineers do:

• Techniques for gene cloning enable

scientists to prepare multiple identical

copies of gene-sized pieces of DNA.

• Cloning means to make copies, in this case,

copies of genes. We also use the word to

describe making copies of cells or

organisms.

• Did you know you can now have your dog

cloned?Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

• Genetic engineering was made possible by the

discovery of restriction enzymes that cut DNA

molecules at specific locations.

• In nature, bacteria use restriction enzymes as a

defense chemical to cut foreign DNA, such as

from viruses or other bacteria.

• Most restrictions enzymes are very specific,

recognizing short DNA nucleotide sequences and

cutting at specific points in these sequences. Let’s

watch Choose Restriction Endonucleases.

2. Restriction enzymes are used to make

recombinant DNA

Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

http://highered.mcgraw-hill.com/sites/0072437316/student_view0/chapter16/animations.html

• Restriction enzymes cut DNA often in a staggered

way, creating single-stranded ends called sticky

ends on each cut piece.

• These sticky ends will form hydrogen-bonds with

complementary single-stranded stretches on other DNA

molecules cut with the same restriction enzyme.

• This allows any two pieces of DNA from any two

organisms, like you and your dog, to be combined

together, which is one of the big areas of genetic

engineering.


• Here’s a diagram of

how restriction

enzymes can be used

to make recombinant

DNA, DNA that has

been spliced together

from two different

sources. Watch open

the folder, then the

MP4 file.


Fig. 20.2

../Animations/biot11_vid_genengdna.zip

• Recombinant plasmids are produced by splicing

restriction fragments from foreign DNA into

plasmids. Know what plasmids are?

• These can be returned by transformation to bacteria cells

(different bacteria cells than the ones who gave them up).

• Then, as a bacterium carrying a recombinant plasmid

reproduces, the plasmid replicates within it.

• Voila! Clones!!

3. Genes can be cloned with the help of

bacteria cells and their plasmids


• Let’s review with

pictures.

• The process of

cloning a human

gene in a bacterial

plasmid can be

divided into five

steps.

• Now with an

animation.


Fig. 20.3

../Animations/Animation 20.1 Cloning a Gen.MOV

• Just let them reproduce and you have tons of bacteria with your selected human gene in it. One thing you can do is let them make lots of the human protein.

• These include human insulin and growth factor (HFG).

• What would be the advantages over getting these chemicals from a natural source?


• Now that we have lots of pieces of DNA, here’s

another thing we can do.

• One indirect method of rapidly analyzing and

comparing genomes is gel electrophoresis.

• Gel electrophoresis separates macromolecules - nucleic

acids or proteins - on the basis of their rate of movement

through a gel in an electrical field.

• Rate of movement depends on size, electrical charge, and

other physical properties of the macromolecules, just like

what other separation technique that you did with plant

pigments?


• For linear DNA molecules, separation depends

mainly on size (length of fragment), shorter pieces

move more easily through the gel, therefore travel

further than larger pieces. Watch open folder &

MP4


Fig. 20.8

../Animations/electrophoesis.zip

• So-called DNA profiling can be used to identify

the criminal or father in a paternity suit because the

pattern of a person’s bands from electrophoresis of

their DNA is like a supermarket bar code, it is

unique.

• So if the criminal left some of their DNA at the

crime scene, here’s what you do: watch first the

one on Rest. Frag. Length Polymorphisms

• We start by adding the same restriction enzyme to each of the three samples to produce restriction fragments.

• We then separate the fragments by gel electrophoresis.


http://highered.mcgraw-hill.com/sites/0072437316/student_view0/chapter16/animations.html

• For our three individuals, the results of these steps show that

individual III has a different restriction pattern than

individuals I or II. Shall we have a Clue??


Fig. 20.10

• One ambitious research project made possible by DNA technology has been the Human Genome Project, begun in 1990.

• This is an effort to map the entire human genome, ultimately by determining the complete nucleotide sequence of each human chromosome.

• An international, publicly funded consortium has proceeded in three phases: genetic (linkage) mapping, physical mapping, and DNA sequencing.

• In addition to mapping human DNA, the genomes of other organisms important to biological research are also being mapped.

• These include E. coli, yeast, fruit fly, and mice.


• The surprising - and humbling - result to date from

the Human Genome Project is the small number of

human genes, 20,000 to 22,000.

• This is far less than expected and only two to three times the number ofgenes in the fruit fly or nematodes.

• Humans have enormous amounts of DNA that doesn’t code for proteins.


• Techniques for gene manipulation hold great

potential for treating disease by gene therapy.

• This alters an afflicted individual’s genes.

• A normal allele is inserted into somatic cells

of a tissue affected by a genetic disorder in a

similar way to how a gene was put into a

bacteria cell.

• For gene therapy of somatic cells to be

permanent, the cells that receive the normal

allele must be ones that multiply throughout

the patient’s life.


• Bone marrow cells, which include stem cells that

give rise to blood and immune system cells, are

prime candidates for gene therapy.

• A normal allele could be

inserted by a virus

into some bone marrow

cells removed from the

patient.

• If the procedure succeeds,

the returned modified cells

will multiply throughout

the patient’s life and

express the normal gene,

providing missing proteins.

Copyright © 2002 Pearson Education, Inc., publishing as Benjamin CummingsFig. 20.16

• Increasingly, genetic engineering is being

applied to environmental work.

• For example genetically engineered

microbes that can extract heavy metals

from their environments and incorporate

the metals into recoverable compounds

may become important both in mining

materials and cleaning up highly toxic

mining wastes.


• Transgenic organisms – is

this Frankensteinish??

• Some crops are made

resistant to cold or salt.

• Down on the “pharm”, these

sheep have some special

milk.


Fig. 20.18

• To develop a transgenic organism, scientists remove

ova from a female and fertilize them in vitro.

• The desired gene from another organism is cloned and

then inserted into the nuclei of the eggs.

• Some cells will integrate the foreign DNA into their

genomes and are able to express its protein.

• The engineered eggs are then surgically implanted in a

surrogate mother.

• If development is successful, the result is a transgenic

animal, containing genes from a “third” parent, even

from another species.


• Scientists are using gene transfer to improve the

nutritional value of crop plants.

• For example, a transgenic rice plant has been developed

that produces yellow grains containing beta-carotene.

• Humans use beta-carotene to make vitamin A.

• Currently, 70% of children

under the age of 5 in

Southeast Asia are deficient

in vitamin A, leading to

vision impairment and

increased disease rates.


Fig. 20.20

• Today, most public concern centers on

genetically modified organisms

(GMO’s) used in agriculture.


So what’s up with this GMO thing?

• Well, let’s watch a couple of videos.

• First 5 min.

• Second 7:04 this one is best if short of time

• Shall we test what you eat?

http://abcnews.go.com/Health/video?id=2337659

http://www.youtube.com/watch?v=jAP6ZtfP9ZQ&feature=related

• As with all new technologies, developments in

DNA technology have ethical overtones.

• Who should have the right to examine someone else’s

genes?

• How should that information be used?

• Should a person’s genome be a factor in suitability for a

job or eligibility for life insurance?

• The power of DNA technology and genetic

engineering demands that we proceed with

humility and caution.


Cloning on a large scale: Making sheep or

controversial embryos

• Dolly the sheep was the first clone of an adult

mammal produced by the technique known as

nuclear transfer. This is called reproductive

cloning. Watch here

• Cloning an embryo to use its cells as embryonic

stem cells (not federally funded in the U.S. right

now) is called therapeutic cloning.

• Both have big moral and legal issues.

../Animations/scnt-lg.wmv

Documents

Selective breeding is a type of engineeringSelective breeding is a type of engineering that we have done for a long time • See how chickens have been changed by using the selection