GENETIC E

NGINEERIN

G

MANIPULATING GENES…

Can we make our food taste better?

Can we make humans live longer?

Can we make X-men like mutants?!?

Let’s start with HOW…

3 BILLION BASE PAIRS…

How can we make this more manageable…

If I wanted to read War & Peace it would be something

quite intimidating…

But I could make it

less scary by

breaking it up into

small segments….

I will read 20 pages a night! I will be done in a little over two months! Piece of cake…

CUTTING UP DNA: RESTRICTION ENZYMESWhat are they?

Enzymes isolated from certain bacteria strains. They cut DNA at very specific sequences of nucleotides.

Hundreds are identified and each cuts at a different sequence

STICKY ENDS

Ex: EcoRI restriction enzyme

Sequence it recognizes: GAATTC, cuts between G & A

Overhanging, single stranded DNA called “sticky” because they could stick back together or to another sticky end

ISOLATING A SPECIFIC GENE

Geneticists look for restriction enzymes to cut DNA fragments containing specific genes of interest.

GENE

Once we have the gene…where do we put it!?

CLONING VECTORS

Used to carry a gene from one organism to another.

Plasmids: commonly used vectors

A small circular piece of DNA, again, coming from bacteria. Separate from prokaryotic DNA, often aid in antibiotic resistance.

Origin of replication: where a replication forms to replicate the plasmid

If scientists were to use EcoRI ( or any restriction enzyme) to cut both a segment of DNA and a plasmid vector

The sticky ends would be complimentary and could stick together.

TRANSPLANTING GENES

Goal: use bacteria to transcribe and translate a DNA sequence to make proteins that some humans cannot make, such as INSULIN

1. Find gene! Cut using restriction enzymes to isolate

2. Make recombinant DNA! Use a plasmid vector to insert gene

3. Cloning DNA- place plasmid vector into a bacterial cell (TRANSFORM) Bacterial cell will then copy plasmid into new cells

4. Expressing the cloned gene: bacteria must successfully transcribe & translate sequence

Recombinant DNA:

the result of combining two different DNA sequences that would not normally go together

Transgenic Organisms: Inserting a foreign gene into an organism which can then

express the gene and pass it on to offspring

DNA FINGERPRINTING

Though we are all 99.9% identical we have been able to find the places where we differ in DNA sequence and use these like a fingerprint.

In non-coding regions, we all have series of repeats. Ex:

GGTTACTAC-GGTTACTAC-GGTTACTAC

Will be different on homologous chromosomes… your mother and father’s repeated sequences were most likely different and you have a copy form each.

READING THE FINGERPRINT

Read the patterns in each column

Where do they match?

Matching patterns come form the same person

HOW DO WE GET THAT PICTURE?

The method we use for separating fragments of DNA is called

GEL ELECTROPHORESIS

Use a gel which is porous…

GEL ELECTROPHORESIS

What makes the DNA want to move through the gel? CHARGE

DNA has a negative (-) charge

For charges, opposites attract

SO WHAT DOES IT LOOK LIKE WHEN IT IS DONE?Bands represent different sized

fragments of DNA

Bigger fragments are closer to the top

Smaller fragments travel faster

DNA dyed so that it can be seen. Colored dyes and fluorescent dyes are used.

Individual segments can be removed and studied

WHAT IF YOU ONLY HAVE A VERY SMALL SAMPLE?We can amplify it, through a method known as…

POLYMERASE CHAIN REACTION (PCR)

What is polymerase? Where have I heard that word before?

Utilizes the efficiency of DNA in replicating itself.

HOW PCR WORKS…

BENEFITS OF PCR

Ability to use very small samples

crime scenes

ancient DNA

Can do many trials and experiments on the same DNA from just one sample