CHAPTER 13Standard 4.9

Genetic Engineering11-8-2012

How can humans manipulate DNA?

13-1

• Selective BreedingChoosing the “best” traits for breeding

All products of selective breeding is artificial selection

HORSES

Even Cows, Sheep, & Pigs

Hybridization

Crossing dissimilar individuals to bring together the best traits of both organismsProduces hybrids

Golden Doodle Puggle

Designer breeds or mutts?

Not to be confused with hybrid cars..

INBREEDING

Inbreeding = continued breeding of similar individuals (ex. pure breed dogs)Has risks… increases breed’s susceptibility to disease & deformities

Golden retrievers - epilepsyDalmations - hereditary deafness

Increasing VariationBreeders can increase variation in a population by inducing mutations   Mutation = any change in DNA    

Mutations can happen randomly, as in this Scottish fold cat. Cat enthusiasts bred these cats from a single cat with a mutation for the ears.

Mutations produce new kinds of bacteria ex. oil-eating bacteria   

Mutations produce new kinds of plantsEx. day lilies, bananas, citrus fruits Polyploid plants have multiple sets of chromosomes. 

13-2 DNA TechnologyGENETIC ENGINEERING technology that involves manipulating the DNA of one organism in order to insert DNA of another organism

= making changes in the DNA code of a living organism

Different techniques are used…

• to extract DNA from cells• to cut DNA into smaller pieces• to identify the sequence of bases in

a DNA molecule• to make unlimited copies of DNA

Bacterial Transformation

The changing of one strain of bacteria into another strain

Plasmid: a circular piece of DNA found in bacteria

F+ bacterium contains a plasmid

F- bacterium does not contain a plasmid

Steps of Bacterial Transformation

1-Remove the plasmid from the bacterium.

Steps of Bacterial Transformation

2-Isolate the gene of interest.

A gene of interest is a piece of DNA that codes for a protein we want more of

Steps of Bacterial Transformation

3-Open the plasmid by cutting it with a restriction enzyme

This leaves “sticky ends”Which need to be the complement of the sticky

ends left on the DNA fragment you want to insert.

Sticky Ends

Sticky EndsThe restriction enzyme EcoR1 cuts the DNA at the sequence GAATTC, between the G and the A

Sticky Ends

Sticky Ends

Steps of Bacterial Transformation

4-Insert the gene of interest

Steps of Bacterial Transformation

5-Insert the plasmid with recombinant DNA into a new bacterium.

Recombinant DNA: DNA produced by combining DNA from different organisms

Steps of Bacterial Transformation

6-The bacteria reproduces itself and the plasmid. All descendants express the inserted gene

Bacterial Transformation

Other Types of Transformation

• Plants:-Use bacteria that insert their plasmid into plant cells-removing cell walls sometimes allows plant cells to take up foreign DNA on their own

Other Types of Transformation

• Animals:-Many egg cells are large enough that DNA can be directly injected

DNA SEQUENCE (Gel Electrophoresis)

- can be used to solve crimes or determine paternity- requires restriction enzyme to cut the DNA , and electrophoresis to separate it

Steps of Crime Scene Investigation or Who the Baby DADDY????

a.)  DNA extraction

b. Making CopiesPolymerase chain reaction (PCR)

used to make multiple copies of genes

c.  cutting DNA – restriction enzymes

d.) separating & analyzing DNA Scientist use gel electrophoresis =

Transgenic Organisms

Contains genes from other species

1.Microorganisms (bacteria)2.Animals (mouse; medical uses)3.Plants (agricultural uses)*GM Crops

Gene causes these mice to glow in the dark. Normally, the gene is found in jellyfish.

http://www.youtube.com/watch?v=n0UzdYRnMtY

Cloning• member of a population of genetically

identical cells produced from a single cell• easy to clone single cell organisms• multicellular organisms more difficult to

clone• a twin is a natural clone• 1997  Dolly the sheep cloned, 1st

mammal

Clones do exist naturally.  These are identical twins.

http://www.youtube.com/watch?v=7tbxN5uwaqA

How to Clone a Sheep

Cloning a Human

CC was the first cloned cat (Rainbow is the original).  CC is short for "Carbon Copy".  What is interesting is the color pattern for the clone is different from the original.

The reason is that the genes for color randomly turn on or off for the skin cells, creating random coloration even on the cloned cat.

How Can Cloning Be Useful?1.  Save endangered species by storing DNA and cloning2.  Make multiple copies of a useful gene (insulin for diabetics)3.  Clone spare parts, like organs or bone marrow4.  Create experimental groups for studying (animals)5.  Clone "special" animals,pets or horses

Click and Clone

http://learn.genetics.utah.edu/content/tech/cloning/clickandclone/

Stem Cells

• Stem Cells unspecialized cells that can develop into specialized cells

• Types of Stem Cells– Embryonic – Adult– Pluripotent