Genetic Engineering

Chapter 15

I. Selective Breeding

A. Only those organisms with desired characteristics to produce

the next generation

C. Example: domesticated animals,

farm animals, plants

B. Humans use selective breeding to pass desired traits on to the

next generation of organisms

Teosinte

Modern

Corn

II. Hybridization

A. Cross dissimilar individuals to bring together the best of

both organisms.

B. Hybrids usually hardier than parents

Scientists and other experts from Texas

AgriLife Research and other Texas A&M

System entities have developed several

new adapted hybrids to help

Southwestern U.S. producers heat up

domestic fresh pepper production.

III. Inbreeding

A. Continued breeding of individuals with similar characteristics

C. Serious genetic problems can result from excessive inbreeding

B. Maintain desired characteristics of an organism

D. Ex: Pure breeds for dogs

1. Greater risk of two recessive alleles = genetic disorder

1. Blindness,

joint deformities

IV. Increasing Variation

A. Sometimes breeders want more variation

1. Use BIOTECHNOLOGY to manipulate genetic makeup

B. New kinds of Bacteria

1. Hundreds of useful bacteria strands have been developed

Ex. Clean up oil spills

2. Used because small and reproduce

quickly

This image shows the surface oil slick from the Deepwater Horizon oil spill.

Research, including this latest study, has identified which bacteria were most

important in breaking down the oil. Credit: Andreas Teske, University of North

Carolina Chapel Hill.

C. New kinds of Plants

1. Prevent chromosomal separation = polyploidy

a. Multiple sets of chromosomes (3N, 4N)

Recombinant DNA

V. Genetic Engineering: Make changes in DNA code of living organism

A. Different techniques1. DNA Extraction: Chemical procedure takes out DNA of cells

2. Cutting DNA: Restriction enzymes cut DNA into smaller

pieces at a specific nucleotide sequence

Recognition sequences

3. Separating DNA: Gel electrophoresis separates fragments by size

Gel Electrophoresis

Page 323

VI. Using DNA Sequence

A. Allows researchers to study &/or compare specific genes

B. Techniques used to read and change DNA sequence

1. Reading sequence through gel

2. Cutting and Pasting: Splicing DNA with fragments of synthetic

DNA = recombinant DNA

3. Making Copies: Polymerase chain reaction (PCR)

VII. Transformation = Cell takes DNA from outside and combines it with own

DNA

A. Bacteria

1. Foreign DNA is joined to plasmid (circular DNA)

3. DNA is inserted into bacterial cell

4. When bacteria reproduces = reproduces the foreign DNA

2. Plasmid has genetic marker = gene to distinguish bacteria

Transforming Bacteria

TRANSFORMING BACTERIA

B. Plants

1. Tumor producing bacterium inserts DNA plasmid

2. Inactivates tumor- insert DNA, plant cell will

take up new DNA

C. Animals

1. DNA directly inserted into nucleus of an egg cell

2. Replace gene with recombinant DNA

VIII. Transgenic Organisms

A. Contain genes from other organisms

B. Biotechnology

C. Help produce important substances

1. Bacteria - used to produce insulin, human growth hormone,

clotting factor because small, reproduce quickly, & easy to grow

2. Animals – study genes, improve food supply

a. Livestock with extra growth hormone = grow faster, less fatty

3. Plants – may contain gene for natural insecticide

IX. Cloning

A. Member of population of genetically identical cells from a

single cellB. 1997 – Ian Wilmut cloned a sheep

C. Process:

1. Egg cell nucleus removed

2. Fused with donor nucleus (original) by electric shock

3. Fused cell divides

4. Placed in surrogate

5. Develops & born (identical to donor nucleus)D. cloned animals may suffer from genetic defects and health

problems.

CLONING DOLLY