Saturday, November 7, 2009

What does a gene array technique do?


Answers:
Come on StingRay, the question wasn't that obscure. A google search for "gene array" brings up 146,000 hits. It's also known as a micro array. A micro array tests an array of genes. The idea is based on Northern blots, which is another way of testing interactions between RNA and DNA.The question a micro array tries to answer has to do with gene expression. It is useful to know, in a given type of cell, which genes are expressed, meaning that they are turned on, and which are not. The array basically looks at the content of transcripts in a cell, meaning the genes that have been made into RNA. When a gene is activated, RNA is produced from that segment of DNA, and then the protein is produced from the RNA (non-coding RNAs are a different topic). Looking at the messenger RNA transcripts, or mRNA, is a way of looking at gene activation.There are various ways of doing it, and you can check the links below for more specific technical information. The short story is that a slide is made that contains a set of short sequences that correspond specifically to different genes. An array might contain tens of thousands of genes. This slide is exposed to transcripts from a cell, and where there are matches, they will hybridize, or interact. So if a slide had 10,000 representations, you could expose it to, say, transcripts from a normal colon cell, and a certain number of genes would interact, meaning that those were turned on in that cell. You could also test lines from various colon cancers, and then see which interactions are the same, and which are different. This is a way of getting information about which genes may be involved in cancer, as well as in the development process that causes cells to define what type they will be.There are various ways of reading out the interaction. Typically, there is a fluorescent signal, and the strength of the signal tells how strong the interaction is, which indicates how highly the gene is expressed. This is all read by computer, and output into a graphic which typically shows upregulated genes in green, and downregulated genes in red. The results are analyzed by statistical methods, and to be sure they are valid, they need to be tested again in biological systems.
Grants Wishes? Give more details because I've been in this industry for 10 years now and never heard of such an animal.
I think you are talking about micro arrays used to screen.

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