DNA MICROARRAYS

PRESENTED BY :- MADHU NATH

INTRODUCTION PRINCIPLE APPLICATIONS ADVANTAGES LIMITATIONS CONCLUSION REFERENCE

MICROARRAY

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INTRODUCTIONDEFINITION : A DNA microarray (also known as DNA Chips or biochip) is a collection of microscopic DNA spots attached to a solid surface. Each DNA spot contains Pico moles of a specific DNA sequences, known as probes.

HISTORY: Microarray technology evolved from Southern blotting. The concept of microarrays was first proposed in the 1980s by Augenlicht and his colleagues.The use of miniaturized microarrays for gene expression profiling was first reported in 1995, and a complete eukaryotic genome( Saccharomyces cerevisiae) on a microarray was published in 1997.

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a) A DNA chip can be manufactured to contain hundreds of thousands of synthetic single stranded DNA sequences.

b) Unknown DNA from a patient is separated into single strands, enzymatically cut and labelled with a fluorescent dye.

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b) The unknown DNA is inserted into the allowed to hybridize with the DNA on the chip.

d) The tagged DNA will bind only to the complementary DNA on the chip. The bound DNA will be detected by its fluorescent dye and analysed by a computer. The red light is a gene expressed in normal cells; green is a mutated gene expressed in tumour cells; and yellow in both cells.

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The principle of DNA microarrays lies on the hybridisation between the nucleotide. Using this technology the presence of one genomic or cDNA sequence in 1,00,000 or more sequences can be screened in a single hybridization.

The property of complementary nucleic acid sequences is to specifically pair with each other by forming hydrogen bonds between complementary nucleotide base pairs.

PRINCIPLE

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1. Sample preparation

2. Purification

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3. Reverse Transcription

4. Labelling

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5. Hybridisation

6. Scanning

7. Normalization and analysis

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HOW DOES A DNA MICROARRAY WORK?

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Discovery of drugs Diagnostics and

genetic engineering Proteomics DNA sequencing Gene expression

profiling Toxicological research Early detection of oral

precancerous lesions In Cancer

APPLICATIONS OF MICROARRAY TECHNOLOGY

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Provides data for thousands of genes. One experiment instead of many. Fast and easy to obtain results. Huge step closer to discovering cures for diseases

and cancer. Different parts of DNA can be used to study gene

expression.

ADVANTAGES

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Expensive to create.

The production of too many results at a time requires long time for analysis, which quite complex in nature.

DNA chips don’t have very shelf life, which proves to be another major disadvantage of the technology.

DISADVANTAGES

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DNA Microarray are one of the most effective invention ever developed. It is a test that allows for the comparison of thousands of genes at once. Microarray technology uses chips with attached DNA sequences as probes for genes expression. Any DNA in the sample that is complementary to a probe sequence will become bound to the chip. The microarray chip can hold sequences from every gene in the entire genome and the expression of every gene can be studied simultaneously.

CONCLUSION

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THANKYOU

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