GENETIC ENGINEERING

Chapter 15

15.1 Selective Breeding

Selective Breeding 1.

intentional breeding of organisms with desirable trait attempt to produce offspring with similar desirable characteristics or with improved traits.

* before genetic engineering. It’s been around for a long time.

Traits may be more milk produced, more meat, grows faster, more eggs, etc.

Interesting Fact

 In the 1950’s, it took 84 days to grow a 5 pound chicken.

 Now it only takes 45 days.

Speed Bump

 What is an example of selective breeding that we discussed earlier this semester?

Super Cow

before genetic ngineering

10,000 BC - Present

 Selective Breeding  Only using select organisms from a group to create next generation  Race horses  Dogs  Corn – altitude  Cattle – meat or dairy  Larger/Taller/Stronger  Miniature horses

Specific Types

 Hybridization  Crossing dissimilar individuals to get an offspring with the best of both traits  Examples  Donkey + Horse = Mule (Horse’s Strength, Mule’s Endurance.

 Pomelo + sweet orange = Grapefruit.

Inbreeding

 Continued breeding of individuals with similar traits.

  Less Diversity = Less Traits.

Inbreeding let’s us keep traits we want in an oragnism.

 Example: Purebred Dogs

Bacterial Mutations

 Cause organisms or organism’s offspring to mutate and hope they turn into something useful.

 Use radiation or mutagens to cause changes  Not super effective with animals  Super effective with bacteria (they grow faster)  Mutate organisms and select the ones with the desired trait.

Polyploid Plants

 Extra Chromosomes = trouble  In people, animals.

 In plants, extra chromosomes work. (Somehow…?)  Use drugs that prevent chromosome separation in meiosis.

 Select the offspring with the desired traits.

What happens if we want something more precise then selective breeding?

 Something quicker?

 Something more specific?

Genetic Engineering

1.

a laboratory technique used by scientists to change the DNA of living organisms 2. attempt to produce offspring with desirable characteristics 3. or with improved traits

Stronger corn stalk with larger ear of corn, with resistance to insects, etc.

Selective Breeding vs. Genetic Engineering 1.

2.

3.

It usually take generations upon generations to see a change occurring by selective breeding. It took several hundreds of years to produce the corn that we know today. Genetic Engineering make the changes a lot faster.

15.2 - RECOMBINANT DNA AND GENE ENGINEERING

1973

 Stanley Cohen and Herbert Boyer  First recombination  First restriction enzyme – EcoR1  Named for bacteria isolated from – E.coli

 1. Took frog DNA and bacteria  2. Cut with restriction enzyme  3. Glued with DNA ligase  4. Placed into bacteria cell  5. Bacteria made frog proteins

Before we begin…

 We talked about  Putting Human Genes into bacteria – insulin  Putting extra cow genes into cows – rBST  What about something just totally crazy.

Spider Goat http://www.youtube.com/watch?v=6egCh0KmjuA

Spider Goat

1973 - Again

 Stanley Cohen and Herbert Boyer  First recombination  First restriction enzyme – EcoR1  Named for bacteria isolated from – E.coli

 1. Took frog DNA and bacteria  2. Cut with restriction enzyme  3. Glued with DNA ligase  4. Placed into bacteria cell  5. Bacteria made frog proteins

Vocab



Genetic engineering - manipulating genes



Recombinant DNA-DNA made from two or more different organisms

Gene Splicing

Example: Human gene from a chromosome is transferred into bacteria.



Insulin - protein hormone that controls sugar metabolism

Before genetic engineering insulin was taken from the pancreases of slaughtered cows and pigs, then purified

1982

 First genetically engineered drug  Insulin

Making Insulin

Step1 in Recombinant DNA

a. DNA ( gene of interest ) such as insulin code is cut out of a persons chromosome b. Restriction enzymes cut DNA between base pairs c. DNA from a plasmid (found in bacteria) is cut open using the same enzyme d. Cut between specific DNA sequence producing “ sticky ends”

Step 1 Recombinant DNA

Step 2 Recombinant DNA

a.

The two are spliced together-enzyme ligase Human DNA Bacteria Plasmid DNA

b.

Recombinant DNA returned to bacteria cell

Step 3 and 4

Step 3:

Cloning  Host cell reproduces / gene reproduces

Step 4:

Screening  Good cells separated from bad  Genetic Marker – an additional gene added to recombinant DNA to determine if making the Recombinant DNA was successful.

Recombinant DNA

Recombinant-DNA technology

Makes it possible to change the genetic composition of living organisms.

Example: Honeycrisp apples     exceptionally crisp and juicy texture flesh is cream colored and coarse flavor is sub-acid and ranges from mild and well balanced to strongly aromatic outstanding flavor and texture can be maintained for at least six months in refrigerated storage without atmosphere modification

Selective Breeding vs. Genetic Engineering 1.

2.

3.

It usually take generations upon generations to see a change occurring by selective breeding. It took several hundreds of years to produce the corn that we know today. Genetic Engineering make the changes a lot faster.

GEL ELECTROPHORESIS

Gel Electrophoresis

1.

2.

3.

4.

5.

DNA is cut into pieces with a restriction enzyme.

The DNA is cleaned up, protein is removed DNA pieces are placed into a gel The gel is placed in an electrophoresis chamber The chamber is plugged in and the pieces of DNA separate according to size

Gel Electrophoresis

Negative electrode Positive electrode

Gel-filled with cut DNA from different people

Running the gel

1.

2.

3.

4.

Plug in the apparatus Current moves through the buffer When the current moves so does the DNA Small pieces move fast then big pieces of DNA small pieces are farther away from the well.

Running the gel

Wells

DNA Fingerprint

DNA fingerprinting uses

1.

2.

3.

4.

Identify people Identify body parts – war, accidents Identify suspects Identify organisms

DNA Fingerprints

Pattern of dark bands on film.

1.

DNA is cut using restriction enzymes 2.

3.

4.

Fragments are then placed in gel Electric charge moves DNA -> + Separate based on size

DNA fingerprint

1985

 DNA fingerprinting enters courtroom  DNA fingerprinting is the ability to match DNA from crime scene with suspect DNA using gel electrophoresis  Gel electrophoresis is when you  1. cut DNA with restriction enzyme  2. pull fragments through gel using charge  3. look at banding that results and match

PCR

Make a huge number of copies of a gene

Southern Blot

 Southern blotting is designed to locate a particular sequence of DNA within a complex mixture.  For example, Southern Blotting could be used to locate a particular gene within an entire genome.

Southern Blot

CLONING

1997

  Ian Wilmut clones sheep – Dolly New-able to clone from ADULT cells  Embryonic cells were already cloned Process 1.

Remove a mammary gland cell 2.

3.

4.

5.

Remove an egg cell from another animal Remove the nucleus from the egg cell Fuse the mammary gland cell with the egg cell without a nucleus Place the new fused cell into a surrogate mother

Cloning Dolly

USES OF GENETIC ENGINEERING

Uses of Genetic Engineering

Medicines: Pharmaceutical companies produce important proteins using bacteria.

 Diabetics  Heart attack patients  Factor VIII (blood clotting protein) medically

Uses of Genetic Engineering

Vaccines: Primarily used to prevent viral diseases such as, polio, smallpox, measles & influenza.

 Herpes II virus  Hepatitis B

GENETICALLY MODIFIED ORGANISMS (GMO’S) 15.3

AND A LITTLE BIT OF 15.4

1980

 Supreme Court OK’s patents for genetically engineered organisms  First patent – Exxon and oil-eating bacteria

Estimated at least 70% of all processed foods contain GMO’s (truefoodsnow.org) 

Crops

 Enhanced taste and quality  Reduced maturation time  Increased nutrients, yields, and stress tolerance  Improved resistance to disease, pests, and herbicides  New products and growing techniques  1986 Tobacco plant genetically engineered  1992 Tomatoes that resist bruising engineered

Not a GMO

GM Products: Benefits and Controversies



Animals

 Increased resistance, productivity, hardiness, and feed efficiency  Better yields of meat, eggs, and milk  Improved animal health and diagnostic methods 

Society

 Increased food security for growing populations

GM Products: Benefits and Controversies



Environment

 "Friendly" bioherbicides and bioinsecticides  Conservation of soil, water, and energy  Bioprocessing for forestry products  Better natural waste management  More efficient processing

GM Products: Benefits and Controversies Controversies



Safety

 Potential human health impact: allergens, transfer of antibiotic resistance markers, unknown effects Potential environmental impact: unintended transfer of transgenes through cross-pollination, unknown effects on other organisms (e.g., soil microbes), and loss of flora and fauna biodiversity 

Access and Intellectual Property

  Domination of world food production by a few companies Increasing dependence on Industralized nations by developing countries  Biopiracy—foreign exploitation of natural resources

GM Products: Benefits and Controversies

  

Ethics

 Violation of natural organisms' intrinsic values    Tampering with nature by mixing genes among species Objections to consuming animal genes in plants and vice versa Stress for animal

Labeling

 Not mandatory in some countries (e.g., United States)  Mixing GM crops with non-GM confounds labeling attempts

Society

 New advances may be skewed to interests of rich countries

2003

 Human Genome Project completed  Genome – all of the genes mapped out for an organism  Human Genome Project mapped out 25,000 – 35,000 genes

Goals

 The Human Genome Project was a 13-year, international effort with the main goals of sequencing all 3 billion base pairs of human DNA and identifying all human genes.

 The Human Genome Project pinpointed genes and associated particular sequences in those genes with numerous diseases and disorders.  It also identified about 3 million locations where single-base DNA differences occur in humans.

What We Have Learned

 More than 40% of our proteins are similar to proteins in organisms such as fruit flies, worms, and yeast.  This chart compares the human genome with other organisms.

Gene Therapy

1. Process of changing a gene to treat a medical disease or disorder. 2. Absent or faulty gene is replaced by a normal, working gene. 3. This process allows the body to make the protein or enzyme it needs, which eliminates the cause of the disorder.

Treating Disease — One Example of Gene Therapy

 To deliver therapeutic genes to target cells researchers engineer a virus that cannot reproduce or cause harm.

Treating Disease — One Example of Gene Therapy

 The DNA containing the therapeutic gene is inserted into the modified virus.

Treating Disease — One Example of Gene Therapy

 The patient’s cells are then infected with the genetically engineered virus.

Treating Disease — One Example of Gene Therapy

 In theory the virus will insert the healthy gene into the target cell and correct the defect.