Download After Gel Electrophoresis…

Current Genetic Techniques
How can we use DNA today?
Section 3 - Parts of Chapters 13 & 14
What is genetic engineering?

A process that allows scientists to make
changes in an organism’s DNA code
How do you get a sample of
DNA to use for this?
1) DNA Extraction - Add chemicals to
open up the membranes in the cell and
isolate the DNA
2) Cut the DNA - Add restriction enzymes
to cut the DNA at precise locations
(base sequences) so it is a more
manageable size
DNA Extraction
Cutting DNA with Enzymes
What is gel electrophoresis?

A technique used in genetic engineering
that separates DNA fragments by
applying an electric charge to a porous
gel
Why is gel electrophoresis used?
It puts the DNA in a useable form so it
can be read
 Helps us locate a gene of interest
 Allows us to compare genes

What do you do next?
Read the DNA sequence by analyzing
the bands on the gel
 DNA sequencing 
 Before
the gel was run the DNA segment
was added to a test tube with DNA
polymerase
 DNA polymerase added new bases that
were labeled with colors that could be read
from the gel
Now what?
1) DNA fragments can be cut and added
to DNA from other organisms in order to
make recombinant DNA
2) Copies of genes be made by
performing a polymerase chain
reaction (PCR) technique
These new techniques allow for…
Transgenic organisms
 Cloning
 Genetically modified foods
 DNA fingerprinting

Your turn….
Share with your neighbor one thing that
you would like to use these new genetic
techniques for
 My example - figuring out where I got
my red hair from; or combining my two
favorite fruits

Human Traits
How to use and design a Pedigree Chart
What do you see?
Human Pedigrees

Diagrams showing the phenotypes of a
particular trait over several generations
of a family line
 Females
- circle
 Males - squares
 Colored in - individual showing the trait
 Clear - individual not showing the trait
 Half colored in - carrier of the trait
Is individual 1 TT or Tt?
Write out the possible Punnett
Squares and see…..
Which one works with the family?
1
OR
T
t
Tt
t
Tt
T
Tt
Tt
2?
T
t
Tt
t
Tt
t
tt
tt
What if the trait is held on the X
chromosome?
Your turn…

Begin the worksheets on Pedigrees and
the Green Gene with your seat partners
and start the one for homework