What is a Microarray?
It s a piece of equipment that uses a robot and a computer to compare DNA we understand with DNA we do not. Every cell in our body contains the same 6 feet of DNA. But only a small portion is active (scientists call thisactivity expression) in any one cell. If our cells all contain the same genetic material, how does each group of cells know what its job is and how to carry it out? Why are genes expressed in the proper place? Our eye cells allow us to see, our brain cells enable us to think and remember, our heart cells know their job is to keep the heart pumping. How do they know? The Kellogg Eye Center is one of the first departments in the country to be granted funding from the National Eye Institute to use a microarray to study vision. How Do Cells Know What To Do? Scientists are very interested in this question; they call the activity differential expression. Project Director Anand Swaroop, Ph.D., explains it this way: Think of your genetic make-up as a house. Most of the material
A generic microarray consists of multiple features (spots) of DNA which will be used to determine the levels of mRNA expression in a collection of cells. The DNA for each feature is from a gene of interest and is a probe for the mRNA encoded by that gene. In general you can think of a microarray as a grid of DNA spots. Each spot has a unique DNA sequence, different from the DNA sequence of the other spots around it. Thus each spot will hybridize only to its complementary DNA strand. In this way each spot is acting as a probe to determine the levels of a specific mRNA produced by a collection of cells. The basic idea of using a piece of DNA as a probe to determine the presence of the complementary DNA in a solution goes back a long time. It is the same general technique used in Southern, and Northern blots by molecular biologists every day. The thing that makes microarrays so exciting now is the number of DNA probes that it is possible to place on a microarray. Already there are microar
A microarray is a sequence of dots of DNA, protein, or tissue arranged on an array for easy simultaneous analysis. The most famous is the DNA microarray, which plays an integral role in gene expression profiling. The substrate material is glass, plastic, or a silicon chip. Alternative names for the DNA microarray include gene chip, DNA chip, and biochip. The little bits of DNA are called probes. A microarray can be made in a variety of ways. The most primitive is to merely drop the DNA onto glass slides using pins. More sophisticated techniques employ photolithography, electrochemical approaches, and even inkjet printing — anything that can deliver the DNA to a precise spot accurately. The DNA microarray is a product of the late 1980s and early 1990s, when biotechnology really began to take off. The microarray allows a researcher to perform a sequence of tests on all of the samples at the same time, speeding up research dramatically. Traditional biological experimentation works on thi
(no date) Category: Data mining [incomplete] What is a microarray? A microarray is a tool for measuring the amount of messenger RNA (mRNA) that is circulating in a cell. It is the mRNA that transfers information from the genes from DNA inside the nucleus of a cell to create various proteins. Even though they have the exact same DNA, different cells have different amounts of various mRNA because they need to produce different proteins. For example, only certain cells in the pancreas produce insulin even though the DNA code for producing insulin exists inside all cells. Genes that produce a lot of mRNA are said to be upregulated and genes that produce little or no mRNA are said to be downregulated. Microarrays simultaneously measure the amount of circulating mRNA for hundreds or even thousands of different mRNAs. They have applications in many different research areas. • Because the types and amounts of circulating mRNA effectively distinguish one type of cell from another, microarrays c
There are currently two major platform technologies used for the analysis of gene expression: microarrays and “chips”. Microarrays, as developed in the laboratories of microarray pioneers such as Brown and Schena,3 comprise a large number of genes deposited on to a glass slide, which are used for a multiplex reaction—essentially a large scale dot blot. Nucleic acid (usually DNA) is spotted, in a grid arrangement, on to a solid support such as glass slides or nylon membranes. The microarrays serve as hybridisation targets for cDNA extracted from tissue or cell lysates. The RNA from the sample is reverse transcribed, with the simultaneous incorporation of label, and the resulting cDNA provides a signal when it binds to the complementary DNA. In this review, the spotted DNA is referred to as the target, whereas the labelled cDNA sample is called the probe.
