microarrays of dna
TRANSCRIPT
1
Microarrays of DNA
PRESENTED BYABDULLAH AL MASUD(1202019)ATIQUR RAHMAN(1202053)
12/22/2015
2What is Microarrays of DNA?
An orderly arrangement of DNA sequences on a small solid support, usually a membrane or glass slide, used to quickly survey the simultaneous expression of many genes. Also called DNA chip or biochip.
Figure : DNA Chip
12/22/2015
3What is Microarrays of DNA?
Each spot on a microarray contains multiple identical strands of DNA. The DNA sequence on each spot is unique. Each spot represents one gene. Thousands of spots are arrayed in orderly rows and columns on a solid
surface (usually glass). The precise location and sequence of each spot is recorded in a computer
database. Microarrays can be the size of a microscope slide, or even smaller.
12/22/2015
4History
The concept of microarrays was first proposed in the late 1980s by Augenlicht and his colleagues.
Microarray technology evolved from Southern blotting.
They spotted 4000 cDNA sequences on nitrocellulose membrane and used radioactive labeling to analyze differences in gene expression patterns among different types of colon tumors in various stages of malignancy.
12/22/2015
5Requirements
DNA Chips
Target Sample (Fluorescently Labeled)
Enzymes
Fluorescent Dyes
Proves
Scanner
12/22/2015
6Process
12/22/2015
7Process
1.Sample Preparation
2.Purification
12/22/2015
8Process
3. Reverse Transcription
4. Labeling
12/22/2015
9Process
5.Hibridization
6. Scanning
12/22/2015
10Process
7.Normalization and analysis
12/22/2015
11Image Acquisition and Data Analysis
Gene is Not active in either normal or diseased sample
Gene is active in both normal and diseased sample
Gene is active in normal sample
Gene is active in disease sample
Figure: Small portion of DNA chip after Sacnning
12/22/2015
12Field of Microarrays of DNA
Gene Discovery Disease Diagnosis Drug Discovery Toxicological Research
and many more… …
12/22/2015
13Advantages
Provides data for thousands of genes.
One experiment instead of many.
Fast and easy to obtain results.
12/22/2015
14Limitations
The biggest disadvantage of DNA chips is that they are expensive to create.
Arrays provide an indirect measure of relative concentration
For complexity of designing arrays mammalian genomes DNA array can only detect sequences that the array was
designed to detect The DNA chips do not have very long shelf life.
12/22/2015
15Conclusion
Given the limitations of arrays mentioned above, it would be far preferable to have an unbiased method to directly measure all the DNA or RNA species present in a particular sample. The advent of next generation sequencing technologies combined with the rapid decrease in the cost of sequencing has now made sequencing cost competitive with microarrays for all assays with the possible exception of genotyping. It’s likely that DNA arrays will be fully replaced by sequencing methods within the next 5-10 years.
12/22/2015
16References
http://www.wormbook.org/chapters/www_germlinegenomics/germlinegenomicsfig1.jpg (10/12/15)
http://www.thefreedictionary.com/DNA+microarray (11/12/15) http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4011503/ (13/12/15) http://www.premierbiosoft.com/tech_notes/microarray.html (13/12/15) https://
www.broadinstitute.org/mpr/publications/projects/genomics/Microarray_data_mining_facing%20_the_challenges.pdf (22/12/15)
12/22/2015
17
Thank You!
12/22/2015
18
The End
12/22/2015