Microarray technology.pptx

Illustration of microarray technology

1. 1 Presented By : Suman Nasir Microarray Technology

2. Contents Microarray Technology History Principle Steps of Microarray technology Types of Microarray technology Applications of DNA Microarray Technology Disadvantages Conclusion References

3. Microarray Technology Microarray technology  is a developing technology used to study the expression of many genes at once. It involves placing thousands of gene sequences in known locations on a glass slide called a gene chip. The chip is similar to a computer chip; on the outer part, every chip has many short, synthetic, single-stranded DNA arrangements that, as a group, form the normal gene. Each DNA spot contains  picomoles (10 −12  moles) of a specific DNA sequence, known as  probes  (or  reporters  or  oligos )

4. History Microarray technology evolved from Southern blotting The concept of DNA microarrays began in the mid 1980s. Mark Schena was proclaimed as the “Father of Microarray Technology” Mark Schena Mark Schena

5. Principle: The principle behind microarrays is that complementary sequences will bind to each other. The unknown DNA molecules are cut into fragments by restriction endonucleases ; fluorescent markers are attached to these DNA fragments. These are then allowed to react with probes of the DNA chip. Figure: Microarray technique

6. Steps of Microarray technology

7. Types: DNA microarrays , such as cDNA microarrays, oligonucleotide microarrays, BAC microarrays and SNP microarrays MMChips , for surveillance of microRNA populations Protein microarrays Peptide microarrays , for detailed analyses or optimization of protein–protein interactions

8. DNA microarray There are different types of microarrays, DNA microarrays are the most common that is used to detect mutations in a specific gene’s DNA structure, which can then diagnose diseases and genetic disorders. To create these DNA microarrays, an analyst prints a small glass plate with thousands of short, single-strand DNA sequences which have been synthetically produced. DNA fragments from a patient’s DNA are then added to these synthetically produced sequences. Analyst is then able to detect and identify specific mutations within the patient’s DNA. DNA microarray

9. Tissue microarrays Tiny cores of tissue arranged onto a glass slide Analysis of hundreds of tissue specimens in a single experiment Characteristics of Tissue Microarrays: 50 - 500 tissues or more can be analyzed pe r slide block high throughput relatively low cost can be stained with a variety of stains such as H & E Stained slides can be analyzed with a wide- variety of techniques

10. Example: Oligonucleotides are synthesized on the chip. Presently, the commercial versions of Affymetrix Gene Chips hold up to 500,000 probes/sites in a 1.28-cm 2 chip area. Due to such very high information content (genes) they are finding widespread use in the hybridization-based detection and analysis of such mutations and polymorphisms, as single nucleotide polymorphism. Figure: Affymetrix Gene Chip

11. MICR O ARRA Y AS A GENE EXPRE S SI O N PROFILING TOOL MICROARRA Y AS A CO M P AR A TIV E GENOMICS TOOL DISEASE DIAGNOSIS DRUG D I SCOVE R Y T OXICOLOG I CAL RESEARCH Applications of Microarray Technology

12. Microarray as a Gene Expression Profiling Tool The principle aim of using microarray technology as a gene expression profiling tool is to answer some of the fundamental questions in biology such as "when, where, and to what magnitude genes of interest are expressed. Microarray analysis measure changes in the multigene patterns of expression to better understand about regulatory mechanisms and broader bioactivity functions of genes .

13. Microarray as comparative genomic Tool Microarray technology have widespread use in comparative gene mutation analysis as to analyze and genomic alterations such sequence single nucleotide polymorphisms. In microbiology microarray gene mutation analysis is directed to characterization of genetic differences among microbial isolates, particularly closely related species.

14. Disease Diagnosis Different types of cancer have been classified on the basis of the organs in which the tumors develop. Now, with the evolution of microarray technology, it will be possible for the researchers to further classify the types of cancer on the basis of the patterns of gene activity in the tumor cells.

15. Drug Discovery Microarray technology has extensive application in Pharmacogenomics . Comparative analysis of the genes from a diseased and a normal cell will help the identification of the biochemical constitution of the proteins synthesized by the diseased genes.

16. Toxicological Research Microarray technology provides a robust platform for the research of the impact of toxins on the cells and their passing on to the progeny. Toxicogenomics establishes correlation between responses to toxicants and the changes in the genetic profiles of the cells exposed to such toxicants. The microarray permits researchers to examine thousands of different genes in the same experiment and thus to obtain a good understanding of the relative levels of expression between different genes in an organism.

17. Disadvantages They are costly to create, demanding many results need a lot of time for analysis, which is already a complicated process, and the chips are perishable and do not survive for a long time, which proves to be a huge disadvantage of this technology. With the availability of new information and developments, researchers will be able to use microchips to pose more complicated questions and to carry out more difficult experiments, which in turn may lead to breakthroughs in the fields of disease diagnosis and drug discovery, amongst others, while working on decreasing the disadvantages.

18. Conclusion: Microarrays are one of the most effective invention ever developed. Microarray allows for the comparison of thousands of genes at once. Microarray technology uses chips with attached DNA sequences as probes for gene expression. Any DNA in the sample that is complementary to a probe sequence will become bound to the chip. Microarray technology is most powerful when it used on species with a sequenced genome. The microarray chip can hold sequences from every gene in the entire genome and the expression of every gene can be studied simultaneously. Gene expression data can provide information on the function of previously uncharacterized genes. 

19. References: http://www.bio.davidson.edu/courses/genomics/chip/chip.html http://www.cs.washington.edu/homes/jbuhler/research/array

20. Thank You