Transcript DNA BIOTECHNOLOGY Bio 102 Lab

DNA BIOTECHNOLOGY
Bio 102 Lab
DNA ELECTOPHORESIS
This technique uses an agarose gel made from
purified seaweed.
It is used to separate DNA molecules according to
their length.
The gel is submersed in a tank filled with a salt
solution that conducts electricity.
DNA samples are loaded into slots
made in the agarose gel.
DNA molecules snake through the gel which has pores in it
that tangles up the larger DNA fragments. The smaller
fragments migrate faster and further.
A fluorescent dye is added to stain the DNA so it will glow
when placed under ultraviolet light.
A photograph can then be taken of the gel plate for analysis
and documentation.
DNA PROFILING
INVESTIGATE A ROBBERY
THE CRIME
A woman was hit on the head in her
home by a thief who escaped with her
money and jewelry. She recovered from
her injuries but cannot remember what
the thief looks like.
You will examine DNA from blood and
hairs from the crime scene and DNA
from blood samples from the victim, her
husband, and a suspect. Then you will
try to establish whether the suspect was
at the scene.
First, the DNA was extracted from the
blood and the hair samples and placed in
test tubes.
Here is the
equipment for
electrophoresis.
The solution in
each dropper
contains the
DNA. The
droppers load the
DNA samples
into the gel.
The scale
measures the
length of each
DNA strand.
When the
electrical
current is
applied, the
DNA strands
travel down the
plate. The
larger ones are
towards the top
and the smaller
ones get all the
way through to
the bottom.
Which DNA
sample
matches the
blood sample
from the crime
scene?
Does the DNA
evidence
place the
suspect at the
scene of the
crime?
INVESTIGATE A WILL
Percy Davis has just died, leaving his vast
fortune to his children, Percy Junior and
Ann. A man named Alistair claims that he
too is one of Percy’s children and demands
his share of the money.
You will examine DNA from Percy, his wife
Harriet, Percy Junior, Ann, and Alistair to
try to establish whether Alistair has any
basis for his claim.
DNA samples
from each
person are
loaded into
the wells.
The DNA
fragments are
drawn through
the gel by
electric current.
If the bands for
two people
have moved
the same
distance, there
is a match of
DNA at this
site.
Which bands
from Harriet
match the
bands of
Percy
Junior?
The bands
highlighted in
Harriet’s profile
match the
bands in Percy
Junior’s profile.
Those are the
DNA fragments
that he inherited
from his mother.
Which bands
from Percy
match the
bands of
Percy
Junior?
The bands
highlighted in green
are the DNA
strands that Percy
Junior inherited
from his father.
You can see that
Percy Junior has
inherited half of his
DNA from each of
his parents.
Now look at the
profiles for
Alistair and An to
see if they also
inherited half of
their DNA from
Percy and Half
from Harriet.
Is Percy the
father of all
three
children?
Is Harriet the
mother of all
three children?
Who is not
Harriet’s
child?
Does
Alistair have
a basis for
his claim for
part of
Percy’s
fortune?
References
http://www.dnalc.org/ddnalc/resources/ele
ctrophoresis.html
http://www.biotechnologyonline.gov.au/pop
ups/int_dnaprofiling.cfm