DNA MICRO ARRAY TECHNIQUE
- 1. Presenting By- Biplob Dey M.Pharm (Pharmacology) 1st Semester DNA Micro Array Technique
- 2. A DNA microarray (also commonly known as DNA Chip or biochip) is a collection of microscopic DNA spots attached to a solid surface. Each known gene or “probe” occupies a particular “spot” on the chip, and varying levels of fluorescent activity show varying levels of gene activity in introduced genetic material . Fluorescently labeled target sequences that bind to a probe sequence generate a signal. Introduction
- 3. • The concept of DNA microarrays began in the mid 1980s. •“Quantitative Monitoring of Gene Expression Patterns with a complementary DNA microarray” reported by Patrick Brown, Mark Schena and colleagues in Science (1995). • Steve Fodor developed scanner for reading the output. • Mark schena was proclaimed as the “Father of Microarray Technology”. Historical Background:
- 4. The core principle behind microarrays is hybridization. Samples are labelled using fluorescent dyes. At least two samples are hybridized to chip. Complementary nucleic acid sequences get pair via hydrogen bonds. Washing off of non-specific bonding sequences .
- 6. How microarray chip is made: Two main agent- 1. Blockers 2. Masks 1.Blockers added to all boxes. 2.Addition of Masks 3.Addition of Nucleotides 4.New Mask 5.Blockers remove
- 7. Spotted DNA arrays (“cDNA arrays”) • Developed by Pat Brown (Stanford) • PCR products (or long oligos) from known genes (~100 nt) spotted on glass, plastic, or nylon support. Gene Chips: Oligonucleotide arrays (Affymetrix) • Small number of 20-25 mers/gene Ink-jet microarrays (Agilent) • Large number of 25-60mers “printed” directly on glass • Four cartridges: A, C, G, and T • Flexible, rapid, but expensive Types of Microarrays:
- 9. Application: 1. In detecting Cancer cells. 2. In Antibiotic