The Central Dogma: DNA --> RNA --> protein
It is quite common for molecular biologists to sequence genes or gene fragments whose functions are initially unknown. Fortunately, the sequences for thousands of genes, and the proteins they encode, are known. This tutorial simulates the gene discovery process.
EXERCISE
There are now many large scale projects for gene discovery. These projects take advantage of the fact that it is straightforward to make DNA copies of mRNAs, called cDNAs. A cDNA "library", containing clones for thousands of genes, can be made using mRNA from almost any tissue from any species. Automated sequencing technologies make it possible to determine the DNA sequences for hundreds or thousands of cDNAs, which can then be identified by database search methods similar to that described in the following exercise. When a cDNA has been sequenced, it is referred to as an Expressed Sequence Tag (EST). Since different genes are expressed in different tissues, at different points in development, and under different environmental conditions, EST projects help us find out which genes, and which biochemical pathways, are important in different cellular contexts.
An example of a small EST project carried out in my lab can be found at http://home.cc.umanitoba.ca/~frist/Research/EST/EST.html.
In the laboratory research environment, Web-based tools are too
akward to use for anything other than the simplest sequence analysis
tasks.
Many labs at the University of Manitoba use a comprehensive
server-based
bioinformatics facility called BIRCH
[http://home.cc.umanitoba.ca/~psgendb] .
To learn more about Unix, see the Manitoba Unix Users' Group (MUUG)
web site [http://www.muug.mb.ca].
Send questions or comments on this web site to frist@cc.umanitoba.ca