DNA Arrays:
A DNA array, also known as a oligo microarray or gene chip, is a powerful tool used in molecular biology and genetics to study gene expression patterns and detect genetic variations. It allows researchers to investigate the activity of thousands of genes simultaneously.
The basic structure of a DNA array consists of a solid support, such as a glass slide or silicon chip, onto which a large number of DNA molecules are immobilized in an ordered grid-like pattern. Each spot on the array contains a known DNA sequence, typically a short segment of a gene or a specific probe designed to hybridize with a particular target sequence.
To perform an experiment using a DNA array, researchers extract RNA from cells or tissues of interest and convert it into complementary DNA (cDNA) through a process called reverse transcription. The cDNA is then labeled with a fluorescent or radioactive marker and applied to the DNA array. The labeled cDNA molecules hybridize with the complementary DNA probes on the array, and the intensity of the signal indicates the level of gene expression.
By comparing the signal intensities between different samples, researchers can identify genes that are upregulated or downregulated under specific conditions, such as in disease states or in response to drug treatments. DNA arrays can also be used to detect genetic variations, such as single nucleotide polymorphisms (SNPs), by designing probes specific to different alleles.
DNA arrays have been widely used in genomics research, allowing scientists to gain insights into complex biological processes, identify biomarkers, and understand the underlying mechanisms of various diseases.