Transcript Microarrays and Gene Expression Arrays

Microarrays and Gene
Expression Arrays
Francisco Millan, Michelle Measar, Gurleen Kaur
Introduction to Microarrays
We are doing research on gene expression of an
anomaly cell compared to a normal cell.
Gene mutations lead to abnormal cell behavior.
This results in altered gene expression which
affects cell function.
Microarrays is a technique used to analyze the
expression of more than one gene within a cell.
Using microarrays, differences in gene expression
between two different cells types can be
pinpointed.
Using a microarray chip is highly efficient in
that it can test for multiple genes at once.
We save time, effort and resources.
So what is a Microarray?
How a Microarray
chip is made.
1. We need the entire sequenced
genome of an organism.
2. Design primers to replicate
each gene.
3. PCR to make multiple copies of
genes that will be used as
probes.
4. Denature the duplex DNA into
single strands.
5. Place microscopic spots of
each single-stranded DNA
gene into ordered rows and
columns on a slide.
Types of Microarrays
1. DNA
a. (Gene Expression)
2. Protein
3. Carbohydrates
4. Antibodies
5. Metabolites
Gene Expression arrays look to see if certain
genes are being expressed in a cell.
Microarray
Methods
1. Collect Tissue
2. Isolate RNA
3. Isolate mRNA
4. Make Labeled DNA copy
(cDNA)
5. Apply cDNA
6. Scan Microarray
7. Analyze Data
Advantages of Microarrays.
1. They provide information on thousand of genes in a
single experiment.
2. Mostly used for gene expression studies.
3. Saves time, effort, resources and are easier to use.
They are cost-effective and relatively cheap- within
the reach of many individual researchers.
4. With this technology, we are developing
improvements in therapy, faster cancer diagnosis
and prognosis.
5. It is still improving and advancing.
Disadvantages of Microarrays
1. Faulty probe sequences can lead to faulty
hybridization and false positive.
2. Reverse transcriptase activity may produce cDNA
mutant and give a false negative.
3. A faulty translation mechanism may not detect
gene expression or proper proteins for cellular
function.
How gene expression and
microarray relate to our article
1. Why gene expression array was used in our
article?
To analyze gene expression patterns
between monozygotic twins of different
ages.
2. What was the conclusion of the gene
expression array?
Gene expression changes with age due to
multiple factors (life-style, environment,
etc…).
Fig. The older MZ twins display the greatest differences in gene expression profiles
between siblings. (Left) Scatter plots showing expression profiles of 3- and 50-yearold twin pairs. (Right) Number of overexpressed and repressed genes obtained by
DNA array analyses in the 3-year-old compared with the 50-year-old twin pair.