A genetically engineered mouse that can grow a human ear!

• Selective Breeding:
Allowing only animals with desired traits to reproduce .

• Crossing (reproducing) different individuals to bring together the best of both organisms
• Produce a Hybrid which are often hardier than parents.

• Breeding of individuals with similar characteristics to maintain these characteristics

13-2: Manipulating DNA
Genetic Engineering : making changes in the
DNA of living organisms
Some tools we use to change DNA:
• DNA Extraction – taking DNA out of the cell
• Restriction enzymes: are special enzymes that cut DNA in specific locations by recognizing certain base sequences
.
..small pieces are easier to work with, study and identify now, let's organize:
• Gel electrophoresis: separates DNA fragments through a gel using electricity

• Cutting and Pasting: we can make new
DNA by combining DNA from different sources  this is called Recombinant
DNA
• Polymerase Chain Reaction (PCR): uses
DNA polymerase to create thousands of copies of a gene

• Transformation – a cell takes & incorporates DNA from outside into its own DNA

1. Take the gene of interest out of the DNA from a human cell
2. Cut it out using restriction enzymes (act like scissors!!)
3. You are left with your “gene of interest”
4. Take a plasmid (ring of DNA) out of a bacterial cell, cut it with restriction enzymes.
5. Place the gene of interest in the plasmid, making a ring again
6. Put this ring back into a bacteria and let it reproduce!!
...and bacteria will reproduce really fast!!!!

• A bacterium inserts a DNA plasmid into plant cells to create new unique plants
• Ex. Plants resistant to pesticides

•DNA is injected into the nucleus of an egg. As the embryo grows the new DNA will be reproduced

Applications of Genetic Engineering:
Biotechnology
• New technology has created a new field of study: Biotechnology
• We can create transgenic organisms – that contain genes from other
Modified Pigglets!

• When an organism contains genes from other organisms.
• Example:
– Scientists are inserting human genes into animals such as goats

• Have been used to study genes and improve the food supply
– Research is under way where goats could be modified to produce spider silk proteins in their milk that could be used in the production of medical sutures and bullet-proof vests

• Modified plants are important in our food supply!
• 25% of all corn grown in US in genetically modified
• Ex. They have natural insecticides, resist herbicides, vitamins

• DNA produced by combining DNA from different sources.
– Genetically engineered cells contain recombinant
DNA
Firefly gene + tobacco plant = glowing tobacco plant!

Cloning: creating genetically identical individuals

• Clone: a member of a population of genetically identical cells produced from a single cell.
• 1997: first mammal cloned. Dolly, the sheep.

13.3- Human
Genome Project
• When: Began in 1990, finished in 2003
• Cost: approx. $3 billion
• What: Sequenced the human genome (all 24 chromosomes)
• Why: To help understand our DNA
• Fun fact:
– The order of almost all (99.9%) nucleotide bases is exactly the same in all people

• Page 337-338
• 1-10, 13, 16, 17, 22, 23