DNA Extraction and Analysis

DNA
o The
o DNA can be extracted from almost any intact cellular tissue (more cells make it
easier)
 Skin, blood, saliva, semen, mucus, muscle tissue, bone marrow, etc.
 DNA
o
DNA can often be extracted long after nuclear
DNA has degraded.

Simple DNA Extraction
o For
only, not feasible for
DNA
o Works well with fruit (Example: Strawberries)
o Step 1
 Physically break apart plant material, usually fruits
o Step 2
 Use a detergent to break apart the cell membrane
o Step 3
 Treat with ethyl alcohol to isolate DNA from remaining proteins and
sugars
o Step 4
 Spool using a glass rod to view a large clump of nucleic acids (DNA)

DNA Extraction
o The organism to be tested is chosen, and a sample is taken from which DNA can
be extracted.
o
o The DNA sample is treated with
usually both DNA and RNA
 Enzymes
 Examples: protease, amylase, etc (
)
 A second enzyme may be applied to
segments for analysis called
to isolate nucleic acids,
DNA into gene

o


enzymes are used to
extracted DNA into
gene sequences.
Make analysis easier during the process of
Enables scientists to isolate specific genes with specific enzymes for use
in genetic engineering.
o Cuts the gene from the chromosome making a sort of gene soup after the removal
of proteins
o Leaves the ends of gene segments “
” with usually 3 exposed
nucleotides on one side of the double helix, so that ends may be rejoined later.

Methods of DNA Analysis
o There are several simple methods used for analyzing DNA

 Gel
o Advanced Methods

(PCR)


Paternity Testing
o Simple method of DNA analysis that
o Paternity Testing Process
 DNA sample taken usually from
in animals
and
in plants. (
does not
contain DNA, but the hair follicle does.)
 DNA isolated in sample through the use of protein “
”
enzymes.
 Sample run on gels or through a gene sequencer to indicate the presence of
certain genes.
 Comparison of genes13 genes present in the child that are not in the mother, but present in the
father make a 99% match.


Polymer Chain Reaction (
)
o Method used in forensic science to
identification or analysis.
o Newer technique used only in
o Only a few cells are needed with this technique.
genetic material for
Amniocentesis
o Method used to analyze the DNA of a mammal (occasionally other animals)
o
o Gaining favor in high
(Ex. Race horses)

Gel Electrophoresis
o Method used to analyze extracted DNA through the distribution of genetic
markers on an
o Smaller genes
on the gel.
Samples extracted through the same process can be easily compared on a single
gel.

Gel Electrophoresis Process
o An
is placed into a mold to dry, then placed
into an electrophoresis chamber.
o DNA extraction is placed in small wells at
of the agar
gel. Each well represents a different sample or individual.
o
is run through a
buffer solution surrounding the agar gel distributing DNA fragments across the
gel
o Fragments separated by the size of the gene segment;
o Negative charged DNA fragments are
from the negatively charged wells to the positive charged end.
o Buffer solution provides a means of transmission for electrical current, but also
keeps DNA samples in place in wells in the gel.

o
of the electrical current determines the
at which DNA moves across the gel.
o
or another Bromine based solution is
applied at the end of the electrophoresis process to
for better viewing under certain bands of light.