DNA CHIPS

DNA chips or microarrays are recent developments for DNA sequencing – the process of determining the precise order of nucleotides within a DNA molecule. A DNA chip is a collection of microscopic DNA spots attached to a solid surface. It is made by immobilizing a number of DNA probes having a different sequence at defined positions on solid surfaces (made of nylon or glass) made of nylon or glass. The probes can be short DNA molecules such as cDNAs or synthetic oligonucleotides.
THE TECHNIQUE OF DNA SEQUENCING:
A DNA chip carrying an array of different big nucleotides can be used for DNA sequencing. A fluorescently labelled DNA test molecule whose sequence is to be determined is applied to the chip. Hybridization occurs between the complementary sequence of the test DNA molecules and the oligonucleotides of the chip. The position of these hybridizing oligonucliotides can be determined by co-focal microscopy. Each hybridizing oligonucleotide represents an 8 nucleotides sequence that is present in the DNA probe. The sequence of the DNA molecules can be reduced from the overlaps between the sequences of the hybridizing oligonucleotides.
APPLICATION OF DNA CHIPS:
• Identification of genes responsible for the development of nervous systems.
• Determination of genes responsible for inflammatory diseases.
• Construction of microarrays for every gene in the genome of E. coli and almost all the genes of the yeast ‘saccharomyces cerevisiae’.
• Expression of several genes in prokaryotes has been identified.
• Detection and screening of single nucleotide polymorphisms
• Rapid detection of microorganisms for environmental monitoring.
CONS OF DNA CHIPS:
The major limitation of DNA chips at present is the unavaibility of complete genomes arrays for higher eukaryotes, including humans.
THE FUTURE OF DNA CHIPS:
These chips have an estimation to come out within the next few years and are proclaimed to help the biotechnologist to capture the function snapshots of the genome in action for higher organisms.
By,
Parth Patel,
T.Y.B.Pharm
DNA Chip

About Alok Nimrani

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