Microarrays or Genechips are a part of the emergent biotechnology. This presentation is about microarrays, their function, how they work, video, lab setting, AP biology question, and step by step function.

1. Microarray
“DNA Chips”
Essence Perry and Landon Tucker

2. How do microarrays work?
1. Isolate mRNA from tissue sample.
2. Make cDNA by reverse
transcription using fluorescent
labeled nucleotides.
3. Hybridization: Apply cDNA mixture
to a DNA microarray. cDNA
hybridizes to DNA on microarrays.
4. Rinse off excess cDNA. Put
microarray in a scanner to measure
the fluorescence of each spot.
Fluorescence intensity indicates the
amount the gene is expressed in the
sample.

3. How does a Microarray work? (Video)

4. What is the microarray used for?
When they were first introduced, DNA
microarrays were used only as a
research tool. Today, DNA microarrays
are used in diagnostic tests for some
diseases. Though less used than gene
sequencing, microarray tests still tend
to be less expensive than sequencing.

5. What is the microarray used for?
Scientists continue today to conduct
population studies. For example, to
determine how often individuals with
a particular mutation actually develop
breast cancer, or to identify the
changes in gene sequences that are
most often associated with particular
diseases. (Genome)

6. What is the microarray used for?
Microarrays are also used to determine
which drugs might be best prescribed for
particular individuals. Genes determine
how each individual handles a drug’s
chemistry. Microarrays are also advancing
the field of pharmacogenomics or
customized/personalized medicine.

7. What is the microarray used for?
Microarrays can also be used to
study magnitude of which certain
genes are turned on or off in
cells. In this case, instead of
isolating DNA from the samples,
RNA is isolated and measured.

8. What is the microarray used for?
Comparing treatments or conditions or
measuring change in gene expression.
➢ Sick cells compared to healthy cells
➢ Cancer cells compared to normal
cells
➢ Cells before vs. after treatment with
drug
➢ Different stages in development of
an embryo

9. Lab Example
When wanting to figure out what genes are affected during
different types of cancer, microarrays are very useful.
Scientists take mRNA from a cancer sample and a healthy
sample and then make cDNA. They will take the cDNA from
the healthy and cancerous samples and pour it on the
microarray where they bond together. The microarray is is
then analyzed individually for the healthy and cancerous,
then together. The merged analysis shows yellow genes that
aren’t affected, green genes that are slowed down from the
cancer, and red genes that are sped up from the cancer.
This proves to be a good experiment because it shows
scientists what genes are affected during different types of
cancer.

10. AP Biology Question
A microarray known as a GeneChip, with most now-known
human protein coding sequences, has been developed to aid in
the study of human cancer by first comparing two to three
subsets of cancer subtypes. What kind of information might be
gleaned from this GeneChip to aid in cancer prevention?
A) information about whether or not a patient has this type
of cancer prior to treatment
B) evidence that might suggest how best to treat a person's
cancer with chemotherapy
C) data that could alert patients to what kind of cancer
they were likely to acquire
D) information about which parent might have provided a
patient with cancer-causing genes
E) information on cancer epidemiology in the United States
or elsewhere