1 Review Describe the process scientists use to copy DNA Use Analogies How is genetic engineering...
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Transcript of 1 Review Describe the process scientists use to copy DNA Use Analogies How is genetic engineering...
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
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.
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.
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.
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 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