1 Review Describe the process scientists use to copy DNA

Use Analogies How is genetic engineering like computer programming

2 Review What is a transgenic organism Compare and Contrast Compare the transformation

of a plant cell with the transformation of an animal cell

3 Practice Design an experiment to find a way to treat disorders caused by a single gene. State your hypothesis and list the steps you would follow

CH 15 GENETIC ENGINEERING15.2 Recombinant DNA

Suppose you have an electronic game you want to change

Game depends on a coded program in a computer microchip

Need to remove the program, change the code and put the modified chip back

Same for genetic engineering.

Copy DNA

Easy to extract DNA Cut using restriction enzymes Use gel electrophoresis.

Douglas Prasher wanted to find a jellyfish gene called green fluorescent protein (GFP)

Protein it makes absorbs energy from light and makes parts of the jellyfish glow

Looked at amino acid sequence protein and predicted mRNA

Cut up jellyfish DNA with restriction enzymes Added his mRNA prediction DNA piece with actual gene on in bonded to the

mRNA Southern Blot test

Technique to find specific DNA sequence by using a segment of nucleic acid.

Polymerase Chain Reaction (PCR)

Technique to make many copies of a DNA segment or gene

1. A piece of DNA is heated, which separates its two strands.

2. At each end a known primer is added Allows DNA polymerase

a place to begin.

3. DNA polymerase copies the region between the primers These copies then serve

as templates for more copies

4. A few dozen cycles of replication can produce billions of copies of the DNA.

Recombinant DNA

DNA produced from combining DNA from different organisms.

Scientists can produce custom-built DNA molecules and insert them into living cells

DNA synthesizers Make short pieces of DNA

Synthetic sequences can be joined to natural sequences using DNA ligase Enzyme that spices DNA together.

Cut DNA using restriction enzyme Results in a chunk of DNA with a sticky end

Cut another DNA molecule with the same restriction enzyme

Sticky ends from the two different molecules can be joined with DNA ligase.

Plasmids

Small circular DNA molecules in bacteria Add DNA to plasmid and then the bacteria it is

located in will duplicate itself and the added DNA.

Plasmids used for genetic engineering contain a start signal - origin of replication (ori), and a restriction enzyme cutting site, such as EcoRI.

Genetic Marker

Gene that makes it possible to distinguish bacteria that carry the plasmid from those that don’t.

In addition to added gene, add a genetic marker such as antibiotic resistance genes tetr and ampr

Grow bacteria in a dish treated with antibiotics and those who survive have the genes.

Transgenic Organisms

Organism that has genes from another speices Produced using recombinant DNA.

Transgenic Plants

Many plant cells can be transformed using Agrobacterium Normally causes plant tumors Deactivate tumor producing gene and replace it with

the gene you want to add to the plant Bacteria infects plant cells Culture those plant cells into adult plants that have

the DNA you added.

Transgenic Animals

Can use same techniques as plants Some egg cells are large enough to inject DNA

directly into the nucleus Also able to remove particular genes through a

similar process.

Clone

Member of a population of genetically identical cells produced from a single cell

Single cell from an adult organism used to grow an entirely new individual that is genetically identical to the organism from which the cell was taken

1952 tadpoles 1997 Dolly.

Nuclear Transplantation

1. Nucleus of an unfertilized egg is removed2. Egg cell is fused with a donor cell that contains a

nucleus from an adult you want cloned3. Diploid egg develops into an embryo, which is

then implanted in the uterine wall of a foster mother, where it develops until birth

Nuclear Transfer is similar.

Inserting Genetic Markers

1. Write a random DNA sequence on a long strip of paper to represent an organism’s genome

2. Have your partner write a short DNA sequence on a short strip of paper to represent a marker gene

3. Using the chart provided, work with your partner to figure out how to insert the marker gene into the genome

Inserting Genetic Markers

1. Apply Concepts Which restriction enzyme did you use- why

2. Use Models What kind of molecule did you and your partner develop