WET LAB DNA Barcoding: From Samples to Sequences - Northwest ...

WET LAB
Wet Lab: Slide #21
[Note: DNA sequencing is more sensitive
at detecting DNA than many of the
DNA gel staining techniques used in
classrooms. Therefore, students who do
not see a DNA band on their agarose gel
in Lab 3 are still encouraged to proceed
with Lab 4 and submit their purified DNA
sample for DNA sequencing.]
36. Show Slide #22, and remind students that their overall goal is to obtain
DNA sequence data from the species they are studying. In the last experiment,
students analyzed their PCR products using agarose gel electrophoresis. Today,
they will prepare their PCR samples for DNA sequencing.
Wet Lab: Slide #22
Using Bioinformatics: Genetic Research
37. Show one of the DNA sequencing tutorials to familiarize students with the
process of DNA sequencing, listed above under Lab 4: Teacher Preparation.
38. Show Slide #23, and review with students the components and logic of
DNA sequencing. DNA sequencing is an adaptation of PCR, and has many of
the same components:
a. DNA Template: The student’s PCR product.
b. Taq DNA polymerase: This is a special DNA polymerase that is used to
copy the DNA and is heat stable, so that the enzyme is not destroyed by the
high temperatures during the PCR.
c. Primers: These are small pieces of DNA that are specific to the sample
being sequenced. They bind to the 5’ and 3’ regions of the gene to be
copied, instructing the Taq DNA polymerase where to start DNA replication.
d. Buffer and water: As this is a biological reaction, we must add buffers that
mimic the inside of the cell for the Taq DNA polymerase to function properly.
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©Northwest Association for Biomedical Research—Updated October 2012